API makes a cheapo Reef master kit- around 25 bucks.
Red Sea makes another "Reef master" kit that has similar tests for about 30 bucks that is a little step up in ease of use..
I havent looked here on SWF, but I would assume they sell the kits. You can always google the kits I listed and find the best price.
They are not most peoples first choice but for the budget minded or lighter reef, they should work just fine.
JMO-Stay away from Hagen kits, they are really scraping bottom for qaulity and price to match.