The Eye of the World is actually the 1st book in The Wheel of Time series.
A couple of years ago, the publisher split in into 2 books, which they sold separately for the YA market,
according to Wikipedia.
So this is probably just the first half of the actual book, being sold separately as promo in the hopes that you'll splurge for the entire thing.
ETA: Oops, already explained while I was still typing.
Might nevertheless be worth it for the hardcore fans, as Wikipedia says that the print edition had an extra prologue and some new illustrations included, if those are included in the e-book.