Oops, I hit submit before I meant to! Duh!

Also, there are plenty of options for your rats besides "I have to give the babies to the pet store for them to be snake food." All you need to do to prevent them from becoming snake food is to charge an adoption fee that is higher than the price of feeder rats at the pet store. Why would someone pay $10 for a rat from you, if all they were going to do is feed it to a snake, is they can pay $5 from a pet store?

You can post fliers, put up notices at pet stores or the local humane society, animal shelter, etc. You can place an ad in the paper, as long as you don't say "Free to a Good Home".

There are plenty of other options, they just take a little effort.