Did you hear of a gift card? That would be the easiest. If you dont want to bother with a bank account etc..
It’s usally a visa or master card etc… You buy it in the bank or I was told its even easier to get one at CVS Pharmacy. But I’m not sure you can add money to those. Walk in to a chase bank, thats where I got one last week, or ask at a cvs. TD also has it. A credit card account is enough to get the card in bank.
What they do is, they ad the cash to the card on the spot and you have a visa for as long as thier is cash in the card. when it becomes empty the card is garbage.