UKDVDR have a 1GB USB Flash Drive with a built in MP3 player for just £2.98.
This price excludes delivery (which starts at £2.10, after VAT, with various options available).
"Can be used either as regular flash pen drive or to play MP3 files stored on it. Takes any standard stereo headphone plug. Great and reliable with a size of a regular pendrive.
On one AAA battery it will last for hours!"
**As well as MP3 files, this can play WMA files.**