If you are able to use it with no color lines or whiteouts, then the only thing that might need to be replaced is the LCD display glass. you can get it on eBay for anywhere from $30 to $45. If you are spending over $70 on the display, you are purchasing the digitizer as well, which you probably don't need…. unless you break it while replacing the glass, which is easy to do.
If you aren't very handy at small item repairs (some of the pieces might be so small that tweezers and magnifying glasses would be useful), then go with the complete display replacement (including digitizer).
Either that or you could have your neighborhood "geek" fix it for you and pay her/him a small fee plus parts. I bet it would be easy to find a techy that would do it for $75 or less… including parts! That's what I would charge.