Whiter Teeth!

I literally try every toothpaste/set/chewing gum which supposedly 'whitens' your teeth, but none of them have yet made a difference.
  I went to my local Boot yesterday and picked these up for around £5 which is quite in expensive, for what they are.
 I've only used the daily one, twice so far, and my teeth already feel so much smoother and shinier!
 I've read quite a lot of reviews on them, and it has 4 out of 5 stars, which is pretty good! So I thought i'd give it a try.

The difference between them are, the one on the left you use twice a day after brushing your teeth, so it gradually whitens your teeth.
 Whereas the one on the right, is a 'quick boost' and is mean't to whiten your teeth instantly!

Does any one else know any good products or sets I good try?