I seen a bunch of them on CL for about $50... seems way too high to me, but i know you would have no problem flipping one for $20



anything cookier than a straight flat rail will probably be worth more:
rails with kinks in them, curved rails, uprails (one end higher than the other)

lower profile stands are also worth more than stands that are bulkier and cannot easily be rode over

generally steel works best as aluminum doesnt slide well

also things like metal boxes, benches and other stuff can be sold as grind boxes


In fact you could easily make your own and sell em.




http://vimeo.com/18180657