[Taqwus]

You're not buying a license for two weeks; you're buying a license to use basically forever. It's not Illwinter's or Shrapnel's problem that you wouldn't take greater advantage of it. You might as well whine about the cost of buying season tickets for an NFL team if you're only planning to attend one or two games.

In your case, you might want to consider buying used, or reselling when you're done with them. So long as resale transfers /everything/ sold with the game, and no installation remains, I think you'd be in the clear. Hell, you could probably legally borrow from friends for those two weeks so long as everything's transferred etc -- e.g. only one installation for each legit purchase at any given time. This is more likely to be feasible than a rental system or a low-cost limited license, or for Shrapnel or Illwinter to implement a Battle.net-style server or whatever.