It is sometimes hard to know how long an ebook is before you buy it. Some publishers offer word counts, some categories with word count ranges, some just undefined categories. So when working out how much book I am going to get for my buck I often have a look over at Fictionwise where word counts are provided.
But when you look at word counts sometimes it doesn't help the cover price make sense. For example if you look at some of the Dark Castle Lord releases from 2007, arranged by book length, you get a distinct lack of pattern. So be aware, a higher price will not always be a larger book. It pays to check.
Enchanted Castle by Kate Hofman, 67849 words, $4.50
The Saxon Bride by C.H. Admirand, 64701 words, $6.50
A Scot's Honor by C.H. Admirand, 50332 words, $4.50
Castle in Spain by Kate Hofman, 49378 words, $6.50
Naked Visions S B D by Veronica Towers, 47948 words, $6.50
Only in Her Dreams by Veronica Towers, 46522 words, $6.50
Lord Draco: T W K by Raquel Taylor, 37894 words, $2.50
Bedeviling Dulcie by S.J. Ronayne, 30436 words, $6.50
My Love, Forever by Kate Hofman, 65761 words, $4.50