Hey all! New poster and new Betta-mom!

a few questions...
Right now I have a divided 2gal-ish tank for two VTs. For water conditioning I use this tiny blue bottle that's called "DeCLOR" I got from my LFS. (picture here:
http://www.wecoaquariumproducts.com/...r%204%20oz.jpg) which says that it "instantly eliminates chlorine and reduces toxicity of common heavy metals".
Is this enough to use? Should I be getting some other conditioner?
I use a drop per gal. I also try to let my tap water sit for several hours before I put my boys back in after a 100% water change.
ALSO, I was just recently at PetSmart and was trying to get a simple water testing kit and was so overwhelmed at the different kinds! I know that I need to test pH levels, but then I saw that there were ALL kinds of testy-type things for all sorts of things like ammonia, nitrate, carbon, etc, AHH! I was just tempted to just get the most expensive kit with the most things on it because I wasn't sure what I was looking for, and I wasn't very keen on asking anyone (like anyone was around anyways

).
What am I looking for!? What's the best "test kit" to buy/find?