The amount of free spins is tiered based on the amount of money you deposit the first time, and in total you can claim up to 100 free spins. The first part of the offer is free spins on Big Bass Splash, which you’ll get when you make your first deposit. While standard sign-up offers usually include a deposit match and some free spins with wagering requirements, this one does things a little differently. The BetMGM casino sign up bonus is a little different to what you might have seen at most other online casinos. Receive 10 - 50 Extra Spins worth 10p on Big Bass Splash. Opt in & deposit £10+ within 7 days & wager 35x to get up to £100.