This is a discussion on Best Pre Paid Cards to use for deposit? within the online poker forums, in the Poker Deposits & Withdrawals section; So seems many "Normal" credit cards are declined for US players. And I read that pre paid cards work so long as they are good
The rate per $100 is 3% $1000 less than 2% from Gemini/Coinbase. Gemini will let you transfer to a wallet 10 times a month for free. Many poker sites give better bonuses if you deposit in crypto.
You can buy crypto directly in many wallets but it is more expensive. https://edge.app that charges 7% to use a credit card, 6.5% for Apple Pay, 3-8% for an in-person deposit, 1% for ACH/bank deposit. I think most wallet are similarly priced as they all use the same services. I haven't used any of the services in the wallet but I would over prepaid debit cards.
Make sure to check how fast the transaction will clear. In general the more you pay the faster it will be available to use. Whatever site you use make sure you can use two factor authenticatin 2FA (a small app that makes sure your money is safer)