If you're in the UK, even for cheap there's good and bad tablets!
The bad: there's an endless variety of form factors that you can probably obtain to run Win8 on, but the likelyhood of getting a return on value for money is questionable. Most of them are [shipped] from asia, and as such you have to factor in delivery times too. 70% will be between 800x400 to 1024x600, which won't be enough to run the Metro apps.
The good (AFAIK): There are only two relatively inexpensive (below £500) tablets that I'm aware of (the two other good/valued ones are over £500)
below: Zoostorm SL8, Acer Iconia W500/W501 - between £450 to £530
above: MSI Windpad 110w, Asus Transformer 121 - between £579 to £800
Of course you can try looking for the 'below' tablets second-hand; I saw the W500 listed at CEX [online]for £329 (b grade).
So have a search! (Hope that helps).
By the way the W500 is 1280x800 @ 10.1"; so can run metro but won't 'snap'
The Zoostorm is 1366x768 @ 11.6" and can 'snap'