This isn't applicable to your situation - which just sounds wack - but a good rule (which is super fact and situation dependent) when you have a friend group with greater disposable income is to be easy and open handed with money when you have it, even to people who can afford it more than you can. It shows that you aren't a tightwad, and your friends will be more forgiving and open handed with you. It's a really delicate balance though, and depends on your friends, but making sure your friends see you as generous but money deprived is better than them seeing you as a miser.

See Dickens for this trope in spades - the lovable guy who is too generous for his own good is virtuous while the Golden Dustman is wicked.