The margin I have to pay for buying the card is very high, not as high as Ethereum ($20-30 [!]) but it's still much higher than something like Polygon or Base if you use their mainnets and not as a token on Ethereum, then the transacction fee is going to be to be a few pennies, just like in the old days of Bitcoin.
You can skip a fee step by using coinbase wallet, it's self custodial and you can import a wallet with a bit of change if you have one into it, then pay directly the bill.
But with current fees, I really don't know if it's worth it the trouble, it's still about 2$.
I actually used Coinbase Wallet but because ETH fees were so damn high and my wallet balance (barely) too low, I burned about $30 in fees trying to swap/bridge to Polygon before I could finally pay the bill
Friendship ended with Ethereum now Polygon is my best friend.