Buy one Sundesa, BlenderBottle GoStak & get one FREE for $9.99 + free shipping at Vitamin World (add 2 to your cart). This is the lowest price we could find by $15. Over 1,000 reviewers rated it a 4.5 out of 5 star rating at Amazon.
Watch this video on GoStak blender: https://m.youtube.com/watch?v=aq0ZnvNm7tU.*