As yor habit grows, so will your interest in different parameters... IMO, good idea to have a master test kit. The most important, though would be the following(in this order): Ammonia, nitrites, nitrates, phosphates(definitely essential during initial cycle)... then, once stable, a good hydrometer, PH, calcium, Alkalinity, and finally magnesium. Hope ya the best!!!
There's nowhere else I'ld rather be... unless, of course, you're buying