I echo Dave's sentiments. Also, keep in mind, the couple of bucks you save on a cheaper kit might end up costing you more in the long run, chemical imbalances needing a lot of potentially expensive chemicals to fix, damage from the result of chemical imbalances, possibly unsanitary conditions (remember, you're putting yourself, family, and friends in your hands - this isn't running water, it needs good quality care to be and stay safe).
TFTestkits has really done all of the hard work for you. Unfortunately, I had to piecemeal my stuff together and it ended up costing me a lot more because I started out on my own before finding TFP. I'd strongly recommend you invest in one of the bundles - it will be worth it!
Good luck!
Take care,
Mo