Good Monitor for less than $100?

I need a decent sized (20" is fine) monitor for the computer I want to buy, if we can't get a bigger TV. If we do get a bigger TV soon, I will use my current TV (a pretty small 24" I think) for a monitor. I don't really know much about monitors, but I want one that I can play games and watch HD videos on. Please leave a suggestion in the comments below. Thanks :).