If you have an impressive junk pile ...err ...treasure pile, chances are there's a spare set of wheels buried somewhere inside that trove. Why spend beaucoup bucks on a grill or fire pit when you have everything you need to build your own and wow your friends with a one-of-a-kind piece. Cut off matching rectangles on the backside of each wheel so that when you join them together it creates a hole where you can put your logs or charcoal. Put the wheels on top of each other back-to-back and weld the back sides together and you're ready to use it as a fire pit…