What can I upgrade in a Dell OptiPlex 9020 SFF with a $50 gift card?

The most noticeable upgrade would be a used graphics card, but the small-form-factor case and Dell power supply make this difficult. Look specifically for a low-profile card that gets all of its power from the motherboard, such as an RX 6400. Make sure it physically fits and check whether your power supply can handle it. A $50 budget may only get you an older, entry-level card, so shop carefully.

Be careful with suggestions for cards like an RX 580 or GTX 1060. They normally need dedicated PCIe power connectors, which the Dell power supply may not have, and adapters can be unsafe. The case also may not fit a full-size card. A low-profile, slot-powered card is safer, but performance will still be limited by the older i5.

I wouldn’t plan on replacing the parts one at a time in this particular system. Dell used a proprietary motherboard, case, and power supply, so many normal upgrades won’t transfer to a future build. You could use the gift card toward storage or accessories, but those won’t improve gaming performance much. Saving cash and replacing the whole computer later would be a better long-term path.

Another option is to sell the OptiPlex as a complete working computer instead of upgrading it. Add that money to your gift card or future savings and look for a used gaming desktop with a standard case, motherboard, and power supply. That will give you a much better upgrade path than trying to force gaming parts into the SFF system.