As far as FREE SHIPPING is concerned from an ecological perspective, it penalizes buyers closer to the seller. In order for the seller, especially a small one such as myself (just under 2000 shipments a year) to attract sales you base the price, plus shipping on a cost factor close to what it where it would be most expensive to ship the package. Say you're like me, based on the east coast, selling a $50 item weighing 12 pounds. You base the cost of your FREE SHIPPING on what it would cost to ship to a major metropolitan area on the west coast, like Los Angeles. That cost, plus the $50 for the item, becomes your selling price, let's say $75.00.
so you list your item for $75.00 and wait for a sale. People on the east coast are penalized because the shipping cost factored in is higher that what it would actually cost for them to buy your product. You likely lose them as a customer. However, that rural customer in a remote area of Washington state or Texas, suddenly sees greater value in your product, shipped from the east coast, 2000 to 3000 miles away because they know it typically costs a ton of money to get things delivered to them. What with gas surcharges and rural delivery fees, that $25 shipping cost gets bumped to $35. With the click of a finger, that buyer has quite literally reduced the gross on that item you're selling by as much as 20%.
I'm typing this very early in the morning and will revisit this post later today but I hope I've made my point.
More and more I feel betweens fees and shipping expenses, that I work for eBay and FedEx, not myself.