Step 1: Get Pallets
You can get pallets from almost anywhere, but when you buy try to get the pallets that have 3 two by fours that haven't been cut so a forklift can pick them up from either direction.
Step 2: Take Apart Pallets.
Take apart 2 pallets so you have 4 solid two by fours that are the same length, sturdy, and not warped. I have a handy demolition bar that makes taking pallets apart easy. Try to save top boards also
Step 3: Find Top and Bottom Pallet
Use two of the best pallets, I used a pallet with a big piece of plywood rather then separate boards. On the top one, take off the two boards on the bottom for future steps.
Step 4: Building
Lay the bottom pallet facing down, I had to take out the bottom board right on the inside of the end of the end boards, on the bottom of the pallet! Set up the two by fours standing up against the end board and the two by four on the corners created by taking out the two boards.
Step 5: Adding the Top
Now that you have the 4 two by fours stable and nailed/screwed in, connect the two by fours with the wood salvages off the top or bottom of a pallet. I only used 4 pieces and it is very solid. Now have someone help you set the top pallet on and center it up according to the standing two by fours.
Step 6: Finishing Up
Nail the top pallet on from the outside into the two by fours and vise versa, then nail/screw from the top down. Now you have your finished work, and if the whole pallet was warped you may need to add a small piece of wood a bottom corner.
Step 7: Modify
Now you could add a your own shelf in between the bottom pallet and the top pallet or add more wood to the back end of the table to hang tools and such on. Very cheap and easy to make! Made mine in about 20 minutes, and you don't need to cut any wood!
The picture it not mine but it alike to it. The pallet on the bottom is the base, unlike the picture. And I do not have the back piece but may add it