WC1: Can't remember - it was a HitSquad re-release, I'm guessing $A20 ~=$US10.
WC2 + Academy: Bundled with the SB16 Dad bought for our first (decent) computer.
Privateer: EA Classics CD - $A20, I think.
Armada: Bundled on a pre-polygons WC collection CD from my cousin.
WC3 + WC4: $A20 from a friend who isn't half the WingNut we are.
WCP: $A70 ~= $US35 at the Sydney Royal Easter Show 1997. That's actually not bad considering new release games are usually $A100. I didn't even expect Dad to buy it for me, so it was a bit of a surprise.
WCSO: Managed to get it during the free release.