There are lots about - e-bay is worth a look .... but what about one of the larger supermarkets ... my local tesco sell them for less than �20.00 Comet, PC World etc
an average 8hr book is about 120Mb - so even a small 512mb player will store 4-5 books
I have a 2 year old sumvision 512 - 10 hours from a single aaa great for travelling
It's not HiFi nor is it an iPOD (so it's not a target!)
but it's good enough when on the move.
For an 8 year old (and a 51yearold also) if it ever gets lost or just stops ... cheap enough not to care.
You can also use it as a USB memory stick at the same time ... so for me it was good enough.
http://www.ebuyer.com/customer/products/index. html?action=c2hvd19wcm9kdWN0X292ZXJ2aWV3&produ ct_uid=107155&_LOC=UK