How much would this be worth?

[Dobie1]

The other thing to think about is are you 'sure' it is a bad DVD drive?

A broken trace or issues with the mod chip can make it look like the DVD drive has gone bad.

The only real way to test that would be to slap in a known working drive and find out.

IMHO the cheepest way to fix a broken xbox is to take another for parts (and hope you don't end up with two with the same broken stuff).

As far as what to offer your buddy - I would suggest $50-$60 assuming he wants to keep his mod chip.