This is the cheapest draft excluder strip that I found on amazon, but I think it's a false economy. I found two problems with it:
1. The biggest problem is that it doesn't compress at all really- if the gap in your door isn't exactly the size of the foam then it either won't shut properly, or it won't really stop the draft.
2. Also, the adhesive doesn't peel off in one piece, so it's difficult to fit.
Considering that a packet of stormguard draft excluder only costs £2-£3 more, it's probably worth going for that instead. In the end that's what I did, but had to this stuff off my door!