[[url=http://[/URL]="http://accessories…"]This[/]="http://accessories…"]This[/] is the best metronome I've ever used. Loud enough to be used when I'm practicing bass or piano at reasonable volumes. Does subdivisions very easily. Not the cheapest, but the cheap ones are pretty worthless.

Assuming he has a stereo. Just make him a CD with various speeds. But it really depends on what he "needs". Some metronomes have the visual element as well as the audio. Actually most dedicated metronomes do. So it's not just a factor of hearing the unit. But it really depends on what gear (if any) he does have. Metronome to one channel of a headphone preamp and a Mic to the other channel and push the mono button. Lets him have the metronome and hear what he's doing. But not exactly cheap if he doesn't already have gear like that. You can pick up metronomes of various sorts at your local music store. Some as cheap as $20. There's probably even an app for it for the iPhone. fmit and KMetronome and others if he had a DAW and ran linux. It depends on what he has, what he wants, and how much is too much.

Assuming you are talking about an electronic metronome and not a mechanical one, he could plug it into a channel of his amp when playing electric guitar and then continue to use that or else use a ghetto blaster when playing acoustic. No headphones necessary.

Thanks for the suggestions. I have sent my buddy the page and he is currently looking it over trying to make a decision. Thanks.