I have not done this myself, but have watched a friend do it and mess up... of course he drives one of those silly 5.0 Fords. If you're going to do it your self than be very careful and patient, it is not as hard as rebuilding an engine and with some experience with mechanical devices it should be no sweat. You should start off by taking it apart and soaking the pieces overnight in a metal bin full of carb cleaner (about $15 for a half gallon). The whole operation shouldn't take more than two or three days.
If you fear messing it up or have zero time, I would say $25 is a very good deal on the rebuild as long as it is quality work.
You should check for vacuum leaks and bad spark plug wires (and plugs) and a clogged fuel filter before you start the rebuild, just to rule those things out first. You should rebuild the carb every 50-70k though, it's too cheap not to have as a regular maintanance item.
------------------
1984 Firebird - Daily driver, 305 LG4, T5 - Hurst short shifter, Edelbrock 600 CFM Performer Carb - Edelbrock Pro-Flow air filter, gutted cat, IROC 16x8 Wheels, Goodyear P215/60/R16, AIWA bargain basement (from Sears of course) CD player
Player accessories: fuzzy dice, eight-ball Shift knob
Check out my ride here
First Kill: 2001 Subaru Impreza WRX Wagon (1 person vs me with 2 passengers)