[quesera]

Why involve the friend at all?

Following your description, couldn't you have just bought the prepaid (debit) card with cash yourself?

Also FWIW "laundering" is a well-defined thing that this is not, and "prepaid credit" is an oxymoron! :)

[itishappy]

I was 12, and most of my store visits were supervised, largely because I didn't drive much.

It certainly felt like laundering, but you raise a great point!

[quesera]

Ah parental supervision, of course!

That's a fair equivalent of government regulation and source of funds attestation requirements, so "laundering" is at least metaphorically correct! :)