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.
Hm, my experiences with e-Bay have been pretty bad (hard to return items or get customer support involved when something is wrong). I’ve had better luck with just random mid-sized buisnesses or directly ordering from the manufacturer.