Well, this reply is gonna make some heads explode, BUT...
Since you need to keep this budget friendly (and there's no shame in that, we've all been there) go to the auto parts store and get 2 or 3 fiberglass repair kits. Line the floor pans, double it up where you have rust holes, triple it up if it's a spot you need to drill a mounting hole through. Contour it to the factory metal. Lay a bunch of fiberglass strips in. Make sure the floor is clean, I mean REALLY CLEAN before you start. This is a temporary fix. I repeat, this is A TEMPORARY FIX. But, take $55 every month and put it in your sock drawer. Don't touch the money, no matter what. Next April you will have the cash to buy the floor pan replacement. Do it the right way then. And, maybe don't take any passengers until you get the metal floor pans in.
Good luck man.
