test kit
basic test kit -- Aquarium Pharmacuticals Master kit $11 fromPetSolutions.com -- has ammonia (2 bottle test kit reads free ammonia not total ammonia), pH, high range pH, nitrite, nitrate. Does not have KH or GH but these are usually pretty stable in a tank.
If you want uncomplicated, go for AquaClear, all media is reusable so no pricy cartridges to replace all the time. Get two sponges. Order online with the test kit for great savings.
While you are there saving so much money, get some appropriate food for the fish you are getting (I really like NewLife Spectrum) Get a filter brush set and a few nets, some dechlorinator (I like Prime - handles amonia and chloramine and chlorine and handy to use if one day the power goes out and you need to detox ammonia fast) Get a heater and thermometer, too, since you've already paid for the shipping you should add to the savings.