We're probably going to have to get rid of our male cat

Ask the shelter if they have a low cost neuter program. If people actually can't afford the surgery in my area, they'll do it for $5 or sometimes even for free. The program is supported by donations. If you live near a vet school, they often also have similar programs. Unfortunately, the adoption rate is pretty low, especially for cats that spray. You can't realistically expect that you drop off the cat and it's going to get adopted. More likely than not, he'll just end up being put to sleep.

Shelters are full of kitties whose only fault was spraying (or "missing" the sandbox). And getting him fixed isn't necessarily going to solve the problem. You specify "male cat," does this mean you have more than one. Is there a new kitty in the house? Maybe he's feeling threatened. Or is there any other kind of stressor in his environment? New furniture, new house...kitties don't like change, it tends to freak them out. Urinary tract infections are also sometimes a cause for spraying. There is a product that you can get at the pet "superstores" like PetSmart or PetCo that is essentially concentrated facial pheromones. The idea behind it is that kitty smells that and thinks "this has been marked facially, there's no need to mark it again." It's not infallible but it's better than giving up on him. And call the Humane Society. Explain your situation and they can probably get you in contact with a group like the one mentioned above, Animal Crusaders, who could help you get him neutered at a more affordable price.

Is there a local chapter of "Animal Crusaders" in your area? They might pay for the operation. Then you could keep your cat.