LL Bean is currently offering their "Junior Original Book Pack" for the low cost of only $9.99! You can get it in lake blue, or pink with green fish. If you want to add monogramming, that's an extra $6, but with FREE shipping all the time, it's easy to justify the added charge. I just ordered one for my son to use in school next year.
If you aren't familiar with LL Bean's products, they're AWESOME to say the least. My mom bought me an LL Bean backpack when I entered 6th grade (some 16 years ago!) and I still have it & it's in great shape, though it's more often than not used as a diaper bag these days. Their products are quality made and at a reasonable price considering the use you will get out of them.