I buy them at the only pet store in a very large area that you can buy mice and/or rats. The mice are $1.50 a mouse no matter what the size is. Which for me works out since all my mice are huge, and Rats are a bit more expensive up to $3 for jumbo's. I have definitely thought about just bulk buying F/T which would be cheaper just don't have a storage place yet, that's easy enough to fix though. Though if buying F/T is cheaper for a good portion of the time at what point is it that people decide to breed rats or mice for their own purposes.