Fidelity has a rewards card you can tie to a brokerage account.
Basically a percentage of whatever you spend gets automatically tossed into your 401k/IRA or whatever you decide to stuff it into.
I have one and have been happy with it.
+1. I switched from BoA card to Fidelity. The interest rate is much higher, 2% reward across the board, and payment is super easy.
Clarify that interest rate refers to interest paid to you for having an account, not the card's interest rate (which I never pay).
