Barnes and Noble has some awesome deals in their Bargin Book section. Here are a few that are still available. You can find more here. Also you get free shipping with orders of $25 or more. That means you could get up to 12 books for around $25. Now that's a steal!
Up, Up, and Away! $1.99 (50% off)
Happy Halloween $1.99 (50% off)
Mickey's Halloween Treat $1.99 (60% off)
A Very Hungry Caterpillar $3.99 (60% off) This is full price at Toys R US when I was window shopping there lastnight.