You can definitely use NOS with your set-up. But unless you go for stronger pistons and rods (not just high compression - make sure to get forged pistons and either forged steel connecting rods, or get your current rods shotpeened). Even with stock internals, you should be able to use a 50 shot safely. Your programmable ECU will help keep everything in tune safely.
However, especially if you want high compression plus higher than a 50 shot, you're probably going to need a higher capacity fuel pump and larger fuel injectors (probably 310 cc's/min would be a good investment). Incidentally, if you get the high compression internals set-up and decide that that's enough extra cylinder pressure to get the power you want, you should be all set with 270 cc/min injectors.
As for pricing, NOS is of course a big savings over super or turbocharging. I'd say you could probably get your NOS hooked up and everything for say $800 to $1,000. The fuel pump and injectors (parts should be $400 to $600, maybe even $700 if you head for top of the line components). I've never researched different brands of NOS, as I've never considered it for my own set-up, but I've never heard bad things about ZEX, while some people in the know don't like Venom systems.
Well I hope this will assist you in your quest for speed. We'll be here if you have more questions.
-JD