I currently have some bull horns on my bike, and i find myself always holding them right about on the curve, which leads to my hands cramping. So i was thinking bout giving riser bars a try. I was wondering if anyone had any reccomendations on a cheap pair of riser bars ( like under 40$). Also i was wondering how to figure out what size i need? I cant find any size markings on the stem or handle bars i already got on.

If any of your friends or family have an old crappy mountain bike try using its bars. I did that and I couldn't be happier. It was pure luck that they fit my stem. If the bars are too small for your stem you can always use shims cut from a can of PBR.

Find an LBS that deals in used bikes. They'll have a big box of cheap steel risers.

right and reducing the number of possible hand positions will decrease your cramping problem

if you're holding your bullhorns at the elbow, then there's a fair chance you prefer a thumb-forward rather than thumb-in grip. you may be cramping because your stem is too long or too low, but changing to risers will only marginally alleviate the height problem, and will likely just give you wrist pain.

try seeing if someone has a shorter stem for you to try out. i think risers/flat bars come 26.0 or larger

I suggest increasing the height of your bullhorns, and getting gloves first.