Ya Home Depot / Lowes. Not sure if you have one of those there, or if the prices would even be the same.
~ $40 for 2x2's
~$15 for ply
~$6 on 1x2 tim
~I already had the mdf stuff for the shelf, but that cost me like $4 when I bought it before.
So ya about that much. I bought a little bit more than I needed on everything so I probably spent closer to $100 total instead of $80 but it could be done in much less. I just didn't want to run out and have to spend extra money on gas and waste an hour going to get more wood. The extra will come in handy for something else eventually.