Don't buy a cheap fork. Just, don't...

Seriously, save more money, triple your budget (it sounds worse than it is since your budget is already really small) and buy a RS Reba or a recon gold R or RL
I keep telling people, it is not the spring in the fork what matters! Ok, it matters a little but if you get any solo air from RS they are basically pretty same in function. What matters a LOT is the damping system. You want to have a an adjustable compression damper and a rebound damper. IN cheap forks you usually just get a rebound damper and that's just not enough. You need to compensate with a higher air pressure and you end up with a harsh feeling fork.

You can deal with your current fork until you get a proper air fork in it. Think of it as a kind of a rigid.

You may now think that you're not yet on a level which would warrant a good fork. You might not be, but you will be. And a Reba will be very good even quite experienced riders. There are always better forks but when considering cost/quality a reba is the way to go in my opinion. Or an X-fusion but those cost a bit more.

There are also manitou forks of which some models are said to be very good with a decent price but I can't comment on those since I've never owned a manitou.