A masterlist of websites that sell bugs
www.isopod.com/ - yeah if you’ve ever wanted orange or dalmatian or albino OR basically any color of isopod aka pillbugs/woodlouse this is your place
shop.bugsincyberspace.com/Live-Pet-Bugs_c5.htm/ - pretty much the best place to get a variety of pet bugs in the usa! they’ve got beetles, mantids, millipedes, and much more.
https://insectsales.com - highly recommend if youre looking to get millipedes, they also sell isopods, mantises, roaches, tail-less whip scorpions and feeder insects.
www.insect-classifieds.com/ - exactly what it sounds like
www.rhinobeetle.co.uk/ - uk based breeder of huge beetles! mostly stag and rhino beetles. They can ship to the usa too (but packages sometimes get confiscated by customs so be warned)
www.ebay.com/ - usually lots of isopods and millipedes for sale, among other things
www.amazon.com/- theyve got live isopods, millepedes, dubia roaches, madagascar hissing cockroach, and mealworms
These are just all I know of im sure there are more. I haven’t purchased from them all so use ur best judgment when purchasing!