To start off with, I cut 2X4s and 2X6s to different lengths and played around with them until I liked the look of them. After sanding them, paint the blocks black. (After painting-I also sanded them a little around the edges to make them look worn.) I picked out Halloween paper and cut it to the block sizes. I mod podged the paper onto the blocks, added a coat on the top, smoothed out the paper, and let it dry. After it was dry, I just cut out vinyl on a Cricut machine and slapped them on the blocks.
Since we had most of the stuff on hand, it only cost me like $4 for the paint and paper. We also made our own mod podge by mixing 50/50 elmer's glue and water and it worked well.
I LOVE the way the turned out. Happy Halloween!