My garage
You can order bulk online, though, that can prove to be too expensive to be worth it for just one snake.
I would check craigslist as there are a lot of people who breed too many and try to sell the extras.
Also, I'm part a facebook group that has quite a few feeder breeders near me, maybe look for a local group on facebook.
Does your local store happen to sell rats live? You may be able to ask them to euthanize the rats for you so you can put them in the freezer, my local pet store will do that depending on who's in the back that day.