If there are breeders or a rescue in your area please look into that before supporting the pet store industry. Pet stores are notorious for selling poor quality animals, and are only trying to make money, instead of actually caring for the animals. Pet store animals are more often than not, unsocialized, inbred animals that are likely to develop many health problems.
On that note, do not believe what the employees at pet stores tell you. They are often misinformed and are trying to sell the stores product to you, regardless of if the product is necessary or even safe for you rat.
If you must buy from a pet store, Petsmart tends to be better than Petco, and they only keep one gender of rat at each store so you have a very low chance of ending up with a pregnant female.
I worked at Petsmart while in school, and when I do have to go to a pet store, I try to support them over others because they at least TRY to do good things for animals... i.e. the not selling of dogs, giving a section of the store to the humane society to place cats for adoption rather than selling them, and the as mentioned housing only one sex of rat in each store.
That said, I know from personal experience: the employees only have any sort of training in the section they work in most, unless they've been there a LONG time. Petsmart's approach to training is to have a basic training upon hiring, and then optional training manuals that you read and take a test on as time goes by... which is how you get raises at Petsmart, a certain amount per test you pass or something along those lines... it's been a while. But if an employee works in the dog and cat section most days, they'll have next to no training on small animals... or, even if they do work in the small animal section, you have no idea how much of this training they've done. So... my advice is to know what you need before you get there, just like you would at any pet store, and if you do ask for advice be sure to know exactly how much experience the person has with rats.
Have you considered a rescue? Checking with rat rescue organizations in your area could be worthwhile. Also, a breeder would be great, and it's really not more expensive to get one from a breeder than from a petstore in some cases.
nepenthes, you are so one of my favorite adopters.
I agree - check for rescues first. If there isn't one nearby, check Petfinder (Petfinder classifieds, too!), or Craigslist, or even in your local paper. If nothing, see if there's breeders nearby. If you have trouble, we can help if you tell us your location.
Petstore rats, even if they look okay, often (not *always*) have health issues, sometimes that you can't see. You won't get a health guarantee with a rescue (at least, a good rescue!), but you'll be saving lives and supporting rescue instead of putting more money into someone's pocket.
although I'd prefer not to go to a pet store, I know from several people that Petsmart is much nicer than petco. I guess there are rumors going around that petco euthanizes a large portion of its birds, etc., and some other shady things.
Petsmart is very active with humane societies to I always prefer to buy from them. They really seem to care about the welfare of animals in general.
I got mine from the local humane society. It came with a certificate for a free vet exam at the vet of my choice! Plus I knew that I was doing a good thing by adopting.
I had no idea how to go about finding a breeder or how to know whether the breeder was any good.