Step 1: Get a bunch of free wood from a Craig's List ad. 5 2x6s, 3 2x4s and some other scraps scavenged from the alley by your house.
I also got a pallet from a guy whose cabinets were delivered on pallets.
Step 2: Rip all the boards in half (2x6s and 2x4s become 2x3s and 2x2s)...