$3/large or xl rat is a freaking bargain price. And that's provided the OP has access to a rat breeder locally. Expect it to be at least double or even triple that price from a pet store which is a more likely scenario for most keepers. I pay $7-8 large and xl and where I'm moving an xl frozen rat is $8.99. Could order online but then there is the issue of having to order in large quantities and have a place to store a couple hundred dollars worth of feeders.
Holy Carp! Dude, get yourself a small chest freezer off Craigslist and order online, rabbit is $2/pound. Or hit up local backyard rabbit, chicken, and quail producers, you can find them in Facebook groups, and they'll gladly sell you their culls.