Some options for basic rat care for those new to rat keeping.
Rats need a reasonable amount of space to call their own, though you will often find that, even in a large cage with multiple hammocks or hidey holes, your rats will cuddle up into one area to be close to each other for sleeping. Aquariums or cages that are mostly made of plastic walls or tubes are not recommended as the air cannot circulate and it's not great for their respiratory systems. Rats also like to be able to climb so a cage with at least a couple levels is a good idea. Bar spacing is also important - if your cage has a wire floor or ramps, the bar spacing should be no larger than 1/2" x 1/2" or they can get a foot stuck. Similarly, bar spacing on the sides of the cage should not be wide enough for them to get their heads through as they can escape and get lost in your home or get their head stuck through and potentially injure themselves badly. Cage floors made of wire can be covered with plastic needlepoint canvas, linoleum, cardboard or fleece cloth for comfort and safety. Also, choosing metal caging that is powder coated tends to result in easier cleaning and the cage continuing to look and smell clean for a longer time than cages that are uncoated metal wire. Here are some links to popular rat cage models and manufacturers:
Critter Nation Cages, which come in a single or double level, and offer a lot of flexibility for cage decor. They've got large doors and wheeled bases. These are definitely large cages that require a bit of space but are relatively easy to keep clean. I would recommend getting the litter guards that clip on the two large full floors or a replacement pan from Bass Pans or you will end up with more litter outside the cage than inside. A lot of sites like Amazon hold frequent sales on the cages, so check around online before buying. They come flat packed and a helper plus a rubber mallet certainly makes assembly easier, though I can attest that a five foot tall woman armed only with a $10 rubber mallet from the local hardware store and determination can put one together all by herself.
Martins Cages also makes very nice, safe cages for rats. These have the wire floored levels with the rat foot safe 1/2" x 1/2" square bar spacing. They're easier to move around for cleaning the whole cages than the Critter Nations and models up to the 695 will fit in most bathtubs for cleaning. These cages also come flat packed with c-rings and a special tool for pinching the rings together. You will get a hand and wrist workout, but they do go together pretty easily if you read the instructions with care. I would also strongly suggest springing for the powder coated wire and the flip top option is also great for ease of cleaning and access.
Quality Cage Company in Portland, OR is also another popular choice, though we have not personally used them in years as we found the Critter Nations and the Martins to fit better in our home. They are definitley worth checking out as they're local to the Pacific Northwest and they also do custom sizes which is nice if you've got a particular spot picked out for your cage that isn't quite the right dimension for a CN or a Martins.
Litter and bedding are really where your odor control and air quality come into play. Changing cages weekly and doing some scooping of litter pans will keep your rats smelling good and breathing easy (and keep your fellow humans happy.) There are so many litters available on the market that it can feel a bit overwhelming. The two main types sold in pet stores are wood shavings and recycled paper bedding. I would NOT recommend wood shavings, and definitely NEVER cedar bedding, since it contains oils that can really irritate or damage a rat's respiratory system. Kiln dried pine and aspen are much safer if you want to go the wood shaving route, but I personally find the shavings to be messy and not all that great at odor control. Paper bedding is the best option in my experience but even that comes in a huge variety of types. There's the hard pelleted type that is great for areas where the rats won't be bedding down or for corner litter pans. This stuff is often marketed as cat litter and can be cheaper in the kitty litter aisle. Popular brands include Good Mews, Yesterday's Mews, Exquisicat and Crown Animal Bedding. The bedding comes in small hard gray or brownish pellets. OkoCat is also a hard pelleted paper bedding but the pellets are smaller and white. There is also a softer version of the recycled paper bedding that looks more like shreds of thick handmade paper. Common brands are KayTee and Carefresh. If you opt for Carefresh, I personally prefer the Carefresh Complete. It usually comes in white or multicolor as opposed to the brown version. It is much less dusty than the plain brown, less processed litter which is always a good thing for everyone's lungs. There are also options like Soft-Sorb (tiny soft pellets of paper, with an option to get it with lavender buds for natural odor control), kapok pellets or shredded crinkle paper like you might find in packing supplies at an office store. I suggest experimenting to see which type seems to work best in your household for cleaning and odor control. You can also go with lining your cage with fleece or flannel and changing or washing it frequently, with just a couple of small plastic litter pans in the corners.
Here's where you can really go wild and try all kinds of objects and options. But the basics tend to be a hut or hiding area of some kind, a hammock or other soft fabric nest option, a food dish, a water bottle and, especially if you have very active young rats, a safe running wheel. For huts and houses, the plastic igloo shaped houses are very popular and easy to keep clean. Your rats may do a little redecorating by nibbling on the openings to the igloos. You can also use cardboard boxes and tubes which can be discarded and replaced when they get nibbled or piddled on. Hammocks can be purchased or made at home. There are lots of folks who make them and sell them online, so a quick search will net you many options if you're not fabric crafty. To make your own, just avoid fabrics that have threads that can come loose and wrap around a foot easily. Flannel and fleece are the best fabrics for making hammocks or covers for the floors of your cage. Your rats will likely also chew on their hammocks over time, so be prepared to replace them relatively often. If they're not badly chewed, fleece and flannel hammocks can be easily machine washed and dried to get any urine scent out. For dishes, I prefer something ceramic for easy cleaning and to deter chewing. Water bottles can be either glass or plastic and I recommend using a bottle brush to clean them out from time to time in case your bottles start to develop some algae. I do not recommend using a water dish inside the cage as they will knock it over or get litter or waste in the water. Bottles are much cleaner and safer. Wheels are often appreciated by younger rats and especially by females. Some males like to run in them, but I've found it's mostly my girls who are heavy runners. When choosing a wheel, you should pick something that is solid plastic, with a closed side, so that tails or feet are not easily caught and injured. Comfort Wheels and Silent Spinners are both safe brands that are super easy to clean.
Food and nutrition is another area where there are tons of options. I will start with what I would NOT recommend - commercial bagged mixes found in most pet stores. A lot of them contain things like alfalfa pellets and cracked corn, neither of which your rats will or should eat and they also frequently use food dyes that are just unneccessary. Instead, I would recommend high quality blocks and/or a homemade grain mix supplemented with fresh veggies. My favorite easy to find block style rat chow is Oxbow. It's palatable and nutritionally complete. Harlan Teklad and Mazuri lab blocks are also a great choice, though they can be harder to find. As to making a good quality grain mix at home, here's my basic base recipe, with all the ingredients being easy to find in the bulk foods section of your local grocery store.
flaked grains like oatmeal and triticale and rye
low or no sugar cereals like rice chex or museli or cheerios
dry tricolor pasta spirals
a small amount of seeds and nuts, particularly unsalted sunflower seeds, slivered almonds, or pumpkin seeds
a high quality, low fat dog food of your choosing (I like Nutro Naturals personally)
Supplement with lots of nice fresh or frozen veggies - have fun experimenting to see what your individual rats fancy. A little fruit is also fine, though too much can lead to soft stools, so feed fruit in moderation. Rats can also have some of what you're having for your own healthy dinner, too. Most of what we can safely eat, they can safely eat with a few notable exceptions. Because rats, unlike humans, have a one-way pyloric valve, they cannot vomit or burp, which means giving them foods or beverages that cause a lot of gas is a really bad idea. Do not give your rats carbonated beverages like soda and avoid dried beans or anything that tends to cause a lot of gas. it won't kill them, but it will make them feel pretty miserable until they can digest it.
Finding a vet who is comfortable treating small animals is very important. In the Seattle area, I recommend Dr. Karen Obegi at Allpet in Shoreline (she sees our rats), Dr. Elizabeth Kamaka at Kamaka Exotic Vet Services in Mountlake Terrace and the staff at Bird and Exotic Clinic in Seattle. There are also other good small animal vets all over the Puget Sound. If you have a dog or cat, I recommend contacting the vet who sees them and asking if their clinic treats rats or if they've got a colleague they can refer you to.
I would also highly recommend RatsPacNW as a great resource for rat info, particuarly with a focus on local services and resources in the Pacific Northwest, encompassing British Columbia, Oregon, Washington and Idaho. You do not have to be a dues paying member to join the Facebook group or to attend one of the social events or public rat shows that the club puts on around the NW. Visit the club's website at www.RatsPacNW.org or join the Facebook group. RatsPacNW hosts shows yearly in Seattle (Ratapalooza), Portland/Hillsboro (Ratfest), Boise (Rat-a-Rama) and Port Orchard, WA. There are also informal social meet ups from time to time and the Facebook group is fun and very active. It's a welcoming organization whether you are new to rats and have a ton of questions or if you've kept rats as pets for years.