I really don’t know… I know the shelter I used to work for would occasionally end up with fish, but not often. Maybe check out craigslist for someone rehoming theirs for free (or low cost if it comes with a setup?) so you know you’re not supporting bad breeding or a bad habit? Hopefully my followers will have some ideas to help you out!
Craigslist is a good idea. Just try not to get too mad at the people who are wanting to get rid of a betta in a tiny bowl. Smile, be polite, and take the betta home to give it proper conditions.