Everdrives / Flashcarts
With Flash Carts, you can play ROM files directly off SD Card on the original gaming consoles, including SRAM saving. If you got a Retrode2, it's the perfectly legal way to keep your classical game collection alive and also play games where the backup-battery is long dead.
PLEASE NOTE: As PayPal thinks Everdrives are against their policies, PayPal payment is currently not available when ordering an Everdrive.
Of course, every other payment method is still available for you.