They should have more than enough money around. But Sam is Jets role model in being extremely wasteful with money.
I believe them when they say they are desperate for cash this season, as I suspect Sam took the house sale money.
I think the plan was they use Fishtank for the capital, the show pays bills, buys houses, and then Sam gets the money for flipping the houses. Sucks to be the "Investors," they listed those houses as assets but I doubt the sale ever even hit a company bank account.
The market kind of sucks for buying and flipping, and doubly so when you do a ton of damage to the house. Even if you were planning to remodel. I'd bet the profit margin on those houses were less than a quarter of a million combined.
Season 5 probably needed to be a frugal reset. They could of bought a house in a more favorable state paid a lawyer to get whatever permits they needed to film for less than they are renting this House for. But this set up was pitched to them by a fan at the end of Season 4 iirc and the Wiggers are paradoxically lazy. I actually think squattertank in a tired but not completely run down house could of been is own kind of fun.