I have had the complete kit for almost a year and am still working on most of the original bottles. The single ammonia test kit states it is good for 50 tests. It comes with a dropper and a test tube!How many tests can you get out of the API master test kit?
The most important ones are ammonia and nitrAte. For some people they never see a spike in nitrIte during their cycling process, since that part can be quite short lived. So if you are very pinched just buy the ammonia and nitrAte for now....these you will always use, even after the cycling process. Whenever you see your fish act strange you will want to check for ammonia just to make sure your tank is still cycled. Forgetting to add dechlorinator to your water during the water change can kill your bacteria colony off, using any sprays near the tank, having cleaning product residue on your hands....