Skip the supafly bolts. Although it's better than what you have now, they're garbage. If you want to go cheap, get
this. It's cheap, and actually superior to the supafly.
If you want the best, find a SLIK Edge III bolt.
If you want something in between, go with the ACP delrin bolts that can be found all over, but the first one I found with a quick search was
here.
And for worth, to your average paintballer, it's worth next to nothing. Many younglings nowadays consider cockers outdated, slow, heavy, and too difficult to work on, so they'd not pay more than $50 for one. However, the older, wiser ones know that cockers when correctly set up are the cats meow for reliable, easy to use setups that never break down, even if they do weigh a bit more and aren't as fast as modern electros.