thats just what i noticed down here for prices, but depending on the gun if its just the gun, shaft and lanyard, for 2 bands and head your looking at 34+tax in fixing it so that would leave his 100 budget at only 66 bucks which is almost laughable to some people (I know because i ran into that with the sawed off magnum which was the cheapest used gun i could find down here) because everyone thinks they have a gold mine and if he pays 100 for a gun that stripped would be looking at about 134 which another 80 bucks he can get an awsome gun for starting out with brand new.
If you go to FAU check out their dive club, some people may go diving with you and loan you their gun here and there so you can see if you like Pnumatic vs band and wood vs metal. I might try a few shore dives and i have an extra gun so K.I.T and if we can get our scheds to line up Ill loan you mine for during the dive.
also spearboard is good for spearfishing needs