You have to be very careful about change properties of water. It is more important to have stable properties than adjusting them.
When my ph gets high I just put some sphagnum moss, which I first boil, in a bag in the tank. When the kh is low I add 1 tsp of baking soda to my 29 gallon tank.
May be able to get a combo test kit on EBay for a low price. Also check out Wall-mart.
For test need ph, ammonia, nitrites, nitrate test to check when the tank has finished cycling. Test for gh and kh good if you have plants. Most important is the ph and ammonia test. There is the item for ammonia test that sticks on the tank too.