One final thing, note that some TFTs can be different sizes, but have the same native resolution.
So you may buy a bigger TFT monitor, but the number of pixels shown is the same. Dont assume buying a bigger monitor gives you more pixels.
For example a 17" square TFT is 1280 x 1024 resolution. If you go up to 19" square it is also 1280 x 1024.
A 17" widescreen TFT monitor is 1440 x 900, but a 19" widesreen TFT is also 1440 x 900.
A 20" widescreen TFT is 1680x1050, but so are most 21" and 22" monitors.
People often put good deals on the HotUKDeals website (for all sorts of things). Why not see if there is a monitor on there
http://www.hotukdeals.com/