Most casinos will not charge a fee for deposits, but crypto wallets do charge fees for transactions. The difference between Solana and Ethereum or Bitcoin is this fee is much lower. It’s so cheap that it’s practically free.
To give you an idea, Solana has on average a $0.00025 per transaction, while Ethereun is between $3 to $10. So yes, there is technically a fee for SOL deposits, but the fee is so minuscule that it’s basically free.