Yes and no, mostly no. I could add a filter that works similar to the "Free shipping by Amazon" checkbox on Amazon.com search results, however that filter would be hardly helpful. It would show products which have Amazon among its sellers, but that's about it. If there is a marketplace seller who listed their item with free shipping, it would not get picked up. The items would be sorted by their lowest marketplace offer excluding shipping. The price showing on the search result will be the buybox price which is determined by Amazon algorithms and is unpredictable. For those reasons I decided that having this filter on my site would just add to the clutter and not create any additional value. Feel free to post a response if you disagree and think that there is indeed a scenario when having that filter would be helpful. Thank you for writing.
I agree with you, if marketplace sellers would not be picked up in the search if they have free shipping it would not be helpful. Thanks for all that you do for this site. I use every time I search on Amazon and I love it!