It’s like a cross between a checking account and a gift card. With a pre-paid card, your parents deposit money onto the card, and can reload more money as you spend it down. In that way it’s similar to a checking account. However, with a checking account you can overdraw you account (spend money you don’t have) and incur hefty overdraft charges ($35 – $50 for each ofterdraft incident, even if you’re $2 overdrawn.) So, like a gift card, you can only spend the money that’s available on the card. If your card has $48 on it, and you want to buy something that costs $50, your card will be declined and you will have to find another way to pay for your purchase.

Also a lot of places still don’t accept american express so if you are looking into that style of account I wouldn’t do it with American express or you might find yourself trying to pay for something and then being told “Sorry we dont accept that here”

Prepaid cards don’t have bank accounts associated with them. Think of a prepaid card as more like a giftcard or Paypal account that can be used anywhere (with the same proviso @mrlaconic made about American Express. You’d be better off with a Visa or Mastercard).