You playing it on the GC right?
Pikmin 2 really isn't all that rare (something like 1/2 million was made) so you might want to try local sales--flea markets and what not.
Two, gamestop has it listed for $40 used but if you get it with the deals (most of the time the offer buy 2 get 2 free on older systems) you'll save a bit on coin on that as well.
Or you can actually get the UK version and just get the boot disc Freeloader. UK versions usually go around $25-30 shipped. Reaon why it's cheaper for Europe is because Nintendo re-released it on the WII over there.