worth, being what one decides is justifiable of cost over time. To me H@LL YES! but then again I just justified buying a 50 inch plasma..
IF 20 bucks ait cheep you may want to consider an occupation change, though i gather you may still be in school.
Moral here is to each there own. For me to make an usb controller out of a joystick of any kind wireless or not, I will only spend time and about 3 bucks. This is because I'm one with the ways of a soldiering iron and electronic skills. Before this I would pay 20$ an adapters.. Currently I'm making a usb to any joystick box (see my link in my sig). Though this is all just a hobby to me. Whatever you diced, the "worth" is measured in the eye of the beholder, and not a generalization.