Which one is better? The short answer: eBay. Amazon’s unreliable review system, that may or may not refer to the product specified, combined with questionable 3rd party vendors who may or may not ship product specified (or ship defective merch), makes Amazon a site to avoid, especially when compared to the transparent process of eBay, where the actual seller and actual corresponding merchandise are clearly indicated. Moreover, eBay’s integration with PayPal is flawless.
Walmart’s Site-to-Store gets an honorable mention in this video review.
Amazon is great for buying books and music. The book reviews are also helpful. However, for everything else, eBay is the way to go. Even with books and music, eBay offers many used items. A used book or CD is often 50% or greater off list price. Trust, reliability, value, discount, budget, and avoiding scams are themes that are important to the online shopping buyer!