I need a computer screen for editing photos (and playing games, but that's another story). Maximum price is around 200$. Sizewise 21-22" would be nice.
Thanks in advance,
Its hard to go wrong with Dell Ultrasharp, they are really nice displays in all sizes.
As mentioned, the preferred display for photo editing is an IPS display. It can be confusing to figure out which displays are IPS. Apple's iMac and Cinema Displays are IPS, and many Ultrasharp's are, but Dell seems to change supplier's on a whim and the technology changes as often.
As of this post, Dell claims their 27" and 30" are IPS, but no mention of what other sizes are.
I think you'll be able to find a monitor for that budget you have.
I would recommend checking Newegg.com or Fry's for prices. They always have great sales on monitors.
Be sure to review websites for reviews or google will work (although you have to take more time to filter through them).
It shouldn't matter how much just be sure to color calibrate your display and that your display is durable (as i've had a monitor die on me).
A fresh, August 2012, ranking from CNET, which includes below US$ 200 monitors: http://reviews.cnet.com/2733-3174_7-924.html
Here are the best budget monitors for photo editing that you can use for gaming as well; ASUS VS239H-P, AOC i2367Fh, ViewSonic VX2370SMH-LED, HP Pavillion 23xi, AOC e2050Swd. Most of them are below the maximum price range you specified. They are not really the best for the job. But they are the best at that price range. I have more information about them on my website, here
I think that is a pretty low price range myself. I would just get what you can afford and then just practice. With that situation you just have to print some pics and see how it performs. You will start to see what colors are not so good and learn to adjust in post accordingly. Depending on what you do it may not be as big an issue as one would think. I fretted over this for way to long and just found out that yes I CAN freak out about this and get all bunched up or just use my computer screen which turns out is totally good enough. I can not tell the difference in most pics ever. Very seldom do I print and say "man that color is so far off that I have to trash this" or readjust. I do understand that there are situations that this would factor in but even doing video I have hardly ever has it been so noticeable that I would start over or go out and spend a 1000 bucks on a screen. I use an iMac and an older one at that. I have a dual screen set up and put all the stuff on the second screen and the print on the main. Works for me.