don't bother, it takes like 5 people to pull it back.
just build hill/drop in or go to the hardware store and buy a regular bungie cord, and if you can't find one long get a few of the longest ones you can find and attach them together by hooking them and bending the hook and duct taping over the hooks.
I don't think it will be as good, but it would be cheaper and easier to pull back. I think the product is sick, but it's really expensive and really only works when you have a bunch of people, to just use it for urban I'd rather just take a few minutes to make a pile of snow and use that for a drop in or have 2 friends slingshot me.