This page includes many different products, and some are better than others. It is not about the cheapest products, but which ones will help the most. I am not claiming that this is the best product, nor am I saying that I have all the answers. I am only giving you the facts that will help you decide what to buy.
First of all, it is important to remember that a single tooth cannot replace a lifetime of healthy brushing habits. If you are not brushing on a regular basis, you will have fewer chances to get good breath (for example). And the good breath doesn't just exist when you have a good brushing habit, but can come from any habit, even a bad one. If you have an unhealthy brushing habit, your teeth will be greasy, your breath will be thin and not as good, and your smile will be less healthy than normal. Secondly, if you want to use these lightening products, there are a few things that you have to keep in mind. If your teeth are very deep, the products will not have an effect on them. If you don't like the taste of your products, then you have to find a different solution.