artchill:
Depends. For the children the OP is talking about who want “spending money”, they should be learning in BM, not trying to get “spending money” or work so the yeshiva can take it away as tuition (a horrible concept in general, having children work just for the school to take it away). For students who want to begin their career, or even have a summer job to get resume experience, I am being sarcastic.
One of the best experiences I have had was my summer job while I was a teen. I led a (mostly) sheltered life up to that point, and it game me exposure to so many different cultures and people which I needed later in my work experiences; It can be a very positive summer activity, even as a late teen.