I've tried a couple like the MadCatz Bluetooth for $29 and it SUCKED!
Couldn't hear a dman thing and mic sensitivity was too much. So I just stuck with official Sony BT which is only like $40.
If you are close enough to plug in, you could try a wired headset. Thy may be cheaper and usually put the mic closer to your mouth, so you don't have to worry about outside noise as much. You could also consider getting a stereo headset, like from Turtle Beach, giving you mic and headphones in one unit. Downside is that you need to be plugged in.
If you are really looking for wireless, pretty much any Bluetooth headset will work, but the official sony one is going to be the easiest to use and setup. It also probably has the best audio quality and noise cancellation. If price is your priority, pretty much any cheap bluetooth headset is going to be similar in quality. The big difference with cheap mics is that they usually lack noise cancellation. But if that's ok, just try whatever you can find for cheap.
I have a plantronics BT headset that I got off ebay for $20. Same one sells for $60 at walmart. Glad I got it off ebay though, cause the quality is only decent. Plan on getting the sony BT though, much nicer unit at a very reasonable price.
