My cheap mouse is starting to go bad (the left button will randomly decide to go unclicked from time to time), and I'm thinking about getting a new one. I'm looking on Newegg, of course, but I thought I'd ask your opinions as well.

This might not qualify for low, but I bought a G300 last year on sale for $30 and have been happy with it. It has 6 extra buttons around the top of the mouse that can be remapped to various keys that I find helpful in RPGs.

I see right now they are closer to $40 on newegg, so it might be worth considering other mice.

How low is "low"?

Well, I'm reconsidering. I think I might just get a really cheap one to get me by for awhile until I can just buy a nice Razor.

I have a corded Microsoft optical mouse that was like $14, and I've had it for five years and it's still going strong. The only issue with it at all is that it's hard to actually CLICK the mousewheel rather than rolling it, so some games with unmappable controls can be really irritating to play (e.g. Jamestown). Thankfully key remappers are available for free and work well.

So that's about as cheap as you can get, and it works great.

DeathAdder or Naga, take your pick.