I would estimate about 30-40(ferring strips are relatively inexpensive and lightweight) for the wood, 30-50 for the foam board, 40-50 for the plastic and 20 for the paint...
all in all less than 200 at most retail depots.

or you can scour local dumpsters, dumps, etc. and find resources and piecemeal it all together.
(not highly recommended though)

Then add any additional chairs, consoles, etc to make it look l337.