Why does a gallon of milk cost more at the convenience store than the grocery store? Because some people are willing to pay the extra money to get in and out quicker at the convenience store. Same can be said for Amazon and eBay. If you shop around, you can almost always find better prices but for some folks, it is just convenient to go to one or two places, buy all your stuff, and pay a bit more for it, e.g. Amazon.
As for Amazon Prime, I've used it for years and been satisfied. I would much rather support my locally owned stores and do for many things. Still, Amazon has one thing I really like and that is reviews on products - especially if it is an expensive product. I've gone into many local stores before and while in the store, used Amazon's reviews to help me pick good products.
The other thing about Amazon is I often find they have exactly the product I want and I am willing to pay extra for the right product versus one that will work but not quite what I want. It really bugs me to spend time shopping local stores only to find they stock the lowest quality, fastest moving version of a product and I end up wasting hours doing that. I can't expect them to have everyone's perfect product but I often will give them a shot.
