the first was about 3 years ago when i was a freshman in HS (i'm a senior now). i made a PKE out of lego's. of all things-lego's and the best part-it worked! it didn't light up or anything but it had the little thing on top that i could move up or down and it was really easy to do. the second cheapiest prop i've made is in the works-my ecto goggles. everything but the mini M&M tube and the paint was free.