I can help you, first avoid Coinbase at all costs, The Best Wallet for gambling payment is Bitpanda, you transfer directly from your bank to your wallet is free ( NOFEE)
exchange Cash to USDT no fee
from Wallet to a casino they charge like 5 to 10 for £900 , if you use USDT they charge about $8 if you use Litecoin is a bit cheaper
P.S. If your account on BC is not VIP 30plus they charge for cashout, I thing they charger like $10 for every $1000
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