Do you by chance get your supplies at a Petsmart? because if you do, print out the prices of the test kits at
www.petsmart.com and take them with you. It will likely save you some money, because they have to match their website prices in the stores.
If you end up not getting the freshwater master test kit, at least get ammonia, nitrite, and nitrate tests. You can also get ph and some other but those three are the biggies.
You can use the search function on the page to get a price for each kit you need.