If you'd rather not spend much, you'll appreciate this Cabas Rucksack. It's a fail-safe choice and a good investment. Another nice option is this Y-3 Backpack. While the price is competitive, be sure that this item will become a valuable addition to your wardrobe. You might also want to consider this Bric's Backpack. The price is very reasonable, but the effect on your wardrobe will be pretty fantastic.
For something in the middle of the price range, you're in luck with this Rag & Bone Backpack in stock and waiting for you. You are guaranteed to fall in love with this item. It's also worth considering this Kara Rucksack. This product is extremely popular and, just as importantly, not too pricey. Take a look at this 3.1 Phillip Lim Backpack too! Great value for your money.