Ya know that black box is kinda like the credit card commercial "Don't leave home without it"!!! As for price follow this link http://www.berrysbait.com/1/01/1003.htm $229 US. I think they really make a diffrerence when the fishing is tough, they don't catch fish but they do attract more fish to your lures. More fish = more biters.
Good luck and tight lines, Jeff laugh laugh