so if you have $100 available on one credit card, and “almost” $200 in the bank, and you get paid in ten days, and your car is going to cost you $500 to fix (you would’ve had another $100 on another credit card, but you are stubborn and want to be able to get around on your own, so you rented a car . . . dumb decision, probably, but you got the cheapest car you could find, and for the shortest period of time possible . . . plus that extra $100 wouldn’t have helped anyway)
anyway . . . is there anybody out there who is really, REALLY good at math and can show me a solution to this word problem?
and iff you’re bad at math but good at praying, please send up a prayer for me to the God for whom no problem is too big, even when it feels that way from my wallet’s perspective . . .
I wanna love You better whatever it takes . . . 
I would keep the rental as long as planned (or as long as financially feasible), then I would bum rides to work with my good friend beck and home with some other good friend and grit my teeth for however many days until 10 days are up and get paid at which time (hopefully) there is at least something like $$ to cover it. If not enough for the whole $500, I would ask the car place if they take partial payment or ask someone you trust for a short-term loan.
There. That’s all I got. Unfortunately it’s a whole lot less than $500!