If you are using Coinbase as a CEX you will need to move funds to a self custody wallet

Firstly, swap assets (eth, btc, usdc) to Solana — the cheapest way to swap/purchase is using Advance Trade as Simple Trade has high fees

Second, go to “Send” and select Solana. Put the address of your self custody wallet. I use Coinbase Wallet but you can also use Backpack or Phantom

Third, once the funds are in the self custody wallet, use a decentralized exchange like Jupiter to swap Solana for Bonk

Fourth, when you want to swap bonk for Solana, go back to Jupiter

Fifth, to get funds back in your Coinbase account, click the receive tab in Coinbase Retail and send the Solana from your self custody wallet there

Hope this helps

Coinbase supports Solana

You can both send and receive Solana and solUSDC