Plumbing and Piping - leaking kitchen faucet

We just bought a 7 year old house and the single-handle kitchen faucet leaks slightly when you turn it on. The leak appears both at the base of the faucet and also midway down the base. We called in a plumber (for a different problem) and he said we'll probably have to replace the whole thing, and that he'd charge between $250 and $400 for it. We really can't afford that kind of expense. Any tips on how to fix/replace it ourselves? Thanks!!!

The quote you got seems to be on the high side. Do you know what brand of faucet you have? If it doesn't say on it, compare yours to the ones on display at a local home center (Home Depot, etc.), and you may be able to determine what your's is. Then it's simply a matter of getting the right repair kit or cartridge to fix it. You can always come back here for additional help.