Urinary infections can lead to crystals blocking his urinary tract and can turn deadly if left untreated. This is especially true in males because their urethra is a lot smaller.
The signs of an infection are frequent trips to the box with not a lot if anything coming out, or frequent accidents outside the box. Also, there could be a pinkish tinge of blood in their urine. If he starts to cry or hiss, his belly swells, he starts hiding or he stops letting any urine out at all it is an emergency.
For financial help. go to www.carecredit.com and apply for instant credit which will allow you to finance his vet visit with no finance charges for a period of time. This vet visit will not be terribly expensive, probably in the $125 to $200 range depending if he is up to date on his shots. If you wait until it is an emergency, it will be much more expensive. This will not clear on it's own unfortunately. Your kitty needs medical attention TODAY if possible. They will take a urinalysis to confirm the condition, empty his bladder if needed, and give him some antibiotics. They may also recommend special foods to prevent it from recurring. Purina One Special Care is one, and Science Diet makes another. Also, any canned food should have an ash content of 3% or less. Please let me know how it goes. If you have any questions at all, please let me know, I will be happy to help! I am sorry that I did not have an at-home answer for you.