This instructable details the steps I have performed to change a desk lamp I already had to use LEDs instead of a fluoro tube.
This project cost me at this time $49.95 Australian for the strip of 30 LEDs. I already had the desk lamp. If i had to buy it it would have cost me ~ $40 Australian. As the LED strip is geared for 12V I used a power pack / wall wart I had spare. If I had to buy a wall wart I guess it would have cost me anoth ~ $20 Australian.
So I guess you could argue that this project really cost ~ $110 Australian which is roughly $75 US.
Check out the individual steps to see what I have done to end up with a quite passable LED desklamp.