what is the most effective store bought teeth whitening system?

I haven't been to the dentist in a long time and I really need my teeth whitened, but I recently got taken off my parents plan so I don't have insurance anymore for the time being and don't have the money to pay out of pocket for a whitening. Can anyone give me specific brands that actually work so I don't waste my money. Please help, I'm desperate
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Crest WhiteStrips...Ultra? Ultra or "super" or something. Works great, and you'll notice results in about 3 days. It's around $25-35, I believe.
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