UTI in male cat?

6 year old fixed cat. Had UTI in past and it cost over $2000 ): last week he was throwing up. (Clear, maybe slightly yellowish) and for the first time in his whole life, I saw him throwing up hairballs. Discharge was also coming from his anus. It was clear, maybe slightly yellowish as well. After two or three days, he was back on his feet, eating, playing ect. He's a relatively healthy happy cat. Now, its happening again. He seems to be in pain. He is licking that area a lot. He eats and drinks normally. I cannot really tell if he's pooping and peeing regularly as he poops outside, but I know that for sure when he isn't sick, he poops and pees all the time. Oh yes one more thing, we installed a cat door a month ago. He kind of is in the swing of things now and even brought in two dead baby garden snakes. You think he is eating something that isn't agreeing with him? Also, are backyard is totally blocked off. He cannot leave our backyard. I am so scared he has UTI. We cannot afford $2000 again. Thank you so much for reading this! 

So basically he's having the on and off symptoms of white discharge coming from his anus as with licking of his anus. I think its coming from his anus.. it may be from his other area? Does he have UTI?? 

Sounds like his anal glands need to be expressed. Is it stinky? Does he scoot his bottom? This shouldn't be more than a $25 or $30 charge.

He doesn't scoot. But yes, it smells like ammonia or something. 

It may be crystals if it's ammonia smelling and grainy looking, but it makes no sense if it looks like it is coming from his anus. The ammonia smell is worrisome, if it's grainy looking more worrisome. When the anal glass leak it's a smell that's difficult to describe. As long as you see no straining in the litterbox and he is urinating normally I would take him into the vet just for an regular exam have the vet check both areas and have the anal glands expressed. I assume you haven't had that done before? If there's a lot that comes out you probably have your answer. Also urine test shouldn't be too much if you can afford that I'd get that done. I'm not sure why a UTI set you back $2000 that's way too pricey. I think your average UTI should be less than $250 for treatment for everything. He needs a vet.

He really does need to vet, and soon. We are not vets here, and we cannot provide diagnoses for you.

Everything you describe is very worrying to me. Please see a vet soon.

How is your kitty?