With orders of $25 of more, Amazon offers the BlenderBottle 28-oz. Classic Loop-Top Shaker Bottle in Clear/Red for $4.23 with free shipping. That's the lowest price we could find by $5, although we saw it for a buck less in May. This BPA-free bottle features a stainless steel wire whisking ball, measurement marks up to 20 oz., stay-open flip cap, gripper bars, and carrying loop.

Note: This item is sold as part of Amazon's "Add-on program" and can only be purchased with an order of $25 or more.