low pressure gauge and spark plug tools are both avalible at autozone for bout 3 bucks each dude. the stock kit got the job done, sure. but i dont think its worth buying one. putt together your own. it will be more cost effeciive and better at what it does!
The 1-20 psi ones work fine. Thats what I usually use. Otherwise get a cheap digital one. They are very accurate and will go down to something like 1 or 2 psi.