I got an email from "Mutuals Online", which is licensed in Oregon. They are offering $500 in signup bonuses. (The email came from Equibase.)
1. You get $300 bonus if you deposit $600 or more within 10 days of signing up. (or 50% bonus on anything up to $600)
2. You get an extra 10% on all winning exotic bets within 30 days of signup, up to a maximum of $200 bonus.
3. You have to bet through your bonus money one time before withdrawing. So, if you get $500 in bonus money, you have to make an additional $500 in bets before withdrawing.
The promotion is called "Big500", and it looks like "Big500" would have to go into the "Referral/How did you hear about us" box on the sign-up form.
I don't have an acct there, so I can't comment on platform or any other aspect.
https://www.mutuelsonline.com/
--Dunbar