The Midland ear plug headsets usually run ~$30 for a 2 pack, but I wasn't all that impressed with them. The speaker which connects to the ear plug will pick up all the noise of you running around (bouncing around on your gear, moving along it). For about the same price you can get
http://www.ebairsoft.com/bowman-style-h ... -1787.html
Keep in mind though, with both that style of headset and the ear plug style (or "secret service style") they will limit your hearing on that side, which is what I hated the most with those.
If you don't want your hearing hindered, I'd look into a handset like this
http://www.ebairsoft.com/element-h250-m ... -2589.html
I have a small handset that I've been using for about 3 months and haven't had an issue of it "giving my position away", though I'd suggest keeping your radio easy to get to so you can adjust the volume as needed.
http://cgi.ebay.com/L-Sp-Mic-ICOM-IC-F1 ... ltDomain_0
Those also have a mini plug on the bottom so you can plug in earphones if you chose (like ipod ones for example).
I would stay away from the chinky Sordin/Comtac copies. They have active sound canceling (or so they say...), but I don't trust the quality of it. The last thing you want is a flashbang going off next to your head and instead of it canceling the sound, it amplifies it. Plus they don't seem to be made all that well.
There are more expensive options for comms, but I'd keep it simple till you can invest the time and money in what you need. You don't wanna drop $500+ for a headset and radio only to find you don't need it.