Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - Threads Tagged with bump starting
Of course you cause a small amount of wear to the clutch & drivetrain every time you bump start (there should be no "bump" if you're doing it well). Nobody can 100% guarantee the financial savings will outweigh the potential maintenance costs, or if you will even incur any maintenance costs.
We have several users who have been using the technique for hundreds of thousands of miles on the same vehicle, with no ill effects. (Yet.)
I do it.
FYI:
Coasting experiment: engine off VS. engine idling - MetroMPG.com