Especially since you have frozen ground back there, I would think that you would want to have the pool checked out! There could be cracks, the pump may not be working, or it needs repairs! Even if an inspector wants a few hundred to check things out, if there is a problem, then you will have something in writing to negotiate lowering the price. Most inground pools out here are taxed on property taxes. Do you want to taxes on something that ends up needing to be filled in with dirt! If you can't afford the inspection, you probably can't afford to maintain this house.