It's considerably cheaper to build your own gym equipment than ever buying it. I remember reading someones efforts to build a human hamster wheel, built from steel tubing which cost ~$300. I know I saw a wooden one built for ~$50 of lumber. IIRC the wooden saw took a mitre saw and a single wood chisel, so with tools included it likely cost less than $100. The wooden human hamster wheel looked considerably sturdier than most wooden furniture capable of holding several people.<p>Exercise and 'medical' equipment go through rigorous testing, mostly to absolve the developer of liability.