Compressors are one effect where its typically very difficult to get a quality result from a cheap pedal.
IMHO a quality compressor starts at $200 new MAP (minimum advertised price)
But definitely check out the link above. That's pretty much gosple.
^^^^^^^^^^ This, this, this, this, this.
Really? You're going to start throwing that crap at us?
There's always a cadre of people who believe that compressors are used to cover up bad technique, or believe that anything that can be done with a comp can be done with your hands. Those people are wrong. That's not what a compressor is for. If that's how you're using it, you're using it wrong. (And if you're anti-compressor, why are you responding to these threads?)
I am sure the more expensive comps are killer but does anyone really need them? This thread is called:
"do I need an expensive Pedal?"
The correct answer is that you need the right pedal. And that is different for everyone. A cheap compressor circuit can suck the life out of your tone and put you off compressors in general. A pedal with 10 knobs and sliders that control everything but the weather works great for those people who like to do that, but not so much for people like me who prefer something more intuitive. Then there's multi-band, multi-engine comps, all with their own issues.
Speaking from personal experience, most live playing situations do not allow you the luxury of tweaking your compressor controls endlessly between tunes. Find something with enough controls to enable you to dial in what you want quickly but doesn't overwhelm you with options. Most times, you're going to set it and forget it.
I'm also in agreement with ddnidd1 that well-built, good sounding units typically run in the $200 range, give or take. You don't need to pay a king's ransom, but don't underinvest either.
Good luck. As you can tell, the rest of us have this all figured out.