No probs, man!
Well,SS is about 20$, if not less, so it's pretty cheep.It's has a a bit outdated engine, but it's still a great one. if you have any questions about SS or it's engine, go visit :
you have forum at that site, as you have notice, so post there if you need infos.
oh, just so you know, the Serious Sam 2 game is coming out in Q2 2004 with complytely new engine, so that could be one of the best engines to work with.