Cheap entry level system, Compucar N2O in a bag kits are $369 shipped on
Group Buy Center . Sometimes the Venom system shows up on there too, but nothing today that I've seen.
The fuel injected kits are all pretty much the same with varying qualities mostly just on the selenoids and the spray nozzle. If the nozzle looks like a piece of pipe with a hole drilled in it, probably not going to have a good spray pattern. Add things like purge kit (gets the air out of the line), remote bottle opener, bottle warmer, progressive controller, etc, the price can climb pretty high.
I or friend's of mine have had good luck with NOS, NX, NW, and Compucar in the past. Also, don't look past the cheaper Venom kits, they do make standard kits just like the others do, not just the 2000 kit that Trapps has.