This question comes up a lot- one example of a 'semi-recent' discussion: https://ball-pythons.net/forums/show...at-distributor
Note- I've ALWAYS raised my own rodents, so I've never tried any of these sources, but list them because they've repeatedly received very good reviews & few if any complaints I'm aware of. Keep in mind that the more business a company does, the greater the chance of a complaint here & there. That doesn't necessarily mean you want to cross them off your list- think about how well they've resolved any complaints & how recent the complaints were. There can also be issues beyond any company's control- for example, delivery mistakes. There may be other, more localized companies that are not as well known as those listed below. Please feel free to share reviews of those you've bought from.
Perfect Prey (in FL) http://perfectprey.com/
Layne Labs (in CA) https://www.laynelabs.com/
Big Cheese (in TX) https://bigcheeserodents.com/
Cold-Blooded Cafe (in Indianapolis, Indiana) https://www.coldbloodedcafe.com/
Rodent Pro (in IN) https://www.rodentpro.com/