I no longer offer "free shipping" unless it can be shipped by USPS for a fixed rate.
You'll find "customers" never appreciate cost of shipping and continue to low-ball for less than shipping alone.
It's come to the point where I'd rather throw something away than deal with the low-ballers.
But the issue of shipping is separate from the issue of the item prices often being too high these days. People are asking maximum perceived value for something, being inflexible, irregardless of shipping concerns.
I would rather charge for shipping as a separate charge instead of setting up my listings as "free shipping". I don't know if that will affect how much I sell though. It seems people are more likely to buy from a listing that says "free shipping". Unless they actually calculate to figure out that the price of the guy charging shipping is often the same as the one with "free shipping". I don't know if anybody actually ships anything "for free". Most all sellers probably just factor that into their item price with free shipping. With shipping costs you would lose money if you actually priced your item before adding the "free shipping".
Then there's the issue with calculated shipping being accurate. I sell a lot of items where I have multiple available of a single item. So ok. I go and package one up and measure and weigh the box, and that gives the buyer calculated shipping cost. What if they buy more than one? Now I might have to use a bigger box and it will be heavier. I feel that I don't trust the calculator, at least if a buyer purchases more than one. Because how does the calculator know if you are going to have to use a bigger box? You might be able to fit both items into the same size box as shipping one.
I have made some low ball offers in the past but usually I'm buying bulk not just buying one.
I am actually selling some items on eBay that are not worth much at all but I don't want them anymore. And I am trying to limit how much I put into our landfills. Trying to care about the environment. So If someone else can use it I'd rather try to sell it than throw it away.