WHSmith £5 off... but £5 off what?

When I bought something in WHSmith yesterday I was given a voucher for £5 off my next purchase. As you might expect, there are conditions to using the voucher - it's only valid between 26 December 2009 and 3 January 2010, and only "when you spend £20 or more in store".

That's fine, but the list of exclusions in small print on the back of the voucher makes me laugh. The offer excludes all:

• Mobile phones

• CDs

• DVDs

• Games and consoles
  

• Stamps

• Tobacco

• Gift vouchers

• Phone cards

• iTunes gift cards

• e-books

• e-readers

• Book tokens

• Theatre tokens

• National Lottery products

It would be easier to list everything I could spend the voucher on. Um, stationery? Birthday cards? Books?