Steam cards are prepaid cards you can get in numerous stores(at least in the US) that have certain amounts of money on them for you to redeem, you usually can get a choice between $5, $10, $20, $50, $100, and $500, which is the highest I’ve seen. It was extremely useful to me when I was a youngin with no credit card or debit card.
LiveLM@lemmy.zip 2 days ago
If you keep them after redeeming them, they can also be used as proof of account ownership in case your account gets hacked and stolen.