With shipping, the Acer will actually be cheaper, so I'd get that. Acer's are good for cheap monitors, I've had a cheap 19" one set up on another PC that runs well. Don't expect incredible quality, but it'll work and the price is right.
Note, however, that the resolution on (most) 22" monitors is 1680x1050. This is the same resolution as on a 20.1" monitor. Therefore, compared to a 20.1" monitor, the 22" will not look as sharp. I used to have a cheap 22" monitor (Sceptre brand, don't get it) that died on me, and I got a high quality 20.1" Dell to replace it. The 20.1" is so much nicer looking, it's really a world of a difference.