Oakley Vault cuts up to 89% off apparel, backpacks, sunglasses, and more during its Back to School Sale, with items starting at $4.99. It's slightly better than our mention from a week ago (which had up to 70% off) and among the best sales we've seen from Oakley Vault this year. Shipping adds $6.58, or get free shipping on orders of $100 or more.