This is a smart move on Amazon's part. Sure, if you have Amazon Prime you really don't think about it a lot but those of you that don't probably appreciate the roll-back to $35.
Amazon confirmed the change on its shipping guidelines and options page, designating which items and regions for delivery are eligible for free shipping. Amazon's free shipping rate, arguably one of the promotions on the site that has been the most popular and vaulted it to its e-commerce throne in years past, has gone up and down over the years. The free shipping minimum has been as low as $25 in the past and was most recently as high as $49.