There have also been times when in the search results, I see listings having free shipping, but when you go into the listing, it's a separate charge. I think this may be some kind of glitch on eBay's part, but it has happened to me a few times.
I've also noticed with the two listing sellers that one listing will have the item listed with free shipping (but higher buy it now price) whereas the other has it lower but with separated shipping cost.
I did try to buy an item recently, buy it now. As soon as I paid, the seller messaged me that the shipping cost would be $20 more than shown in the listing because of an error, and that they could not cover the cost. I was not very pleased and had them issue a refund.
They were a relatively new seller, and their feedback wasn't particularly great. Apparently they sold some printers that didn't work - I probably should have avoided it, but I really wanted the item. They have since relisted it with the higher cost, so I really think they were inexperienced and it was an honest mistake. I just didn't leave any feedback.