Here's one for the Xbox 360 fanboys. The Magazine Group are offering 3 issues of the "360" magazine for only £3. It's normally £2.79 per issue, so 3 for £3 is pretty good.
You can sign up to this subscription, and cancel within the 3 months and you won't be charged any more. But if you don't cancel, they will start to take out the regular subscription price via direct debit (I think!) Even so, it's still a reduction on the cover price from buying it in the newsstand.