Amazon gives non-Prime members free shipping at $35 or more of eligible items. Instead of simply letting users get the product with free shipping, they’ve added a discount that prices it exactly one cent below the $35 limit, while only subsidizing the price with $3.38, which is about half of what they’ll then charge you for shipping.
Depends on what country you live. Here in the Netherlands nobody sells anything on eBay. German sellers that ship internationally always charge a lot more than in the store and they always add shipping on top of it.