With orders of $25 or more, Amazon offers Prime members the Pyrex Prepware 3-Piece Mixing Bowl Set, in Clear, model no. 1118441, for $7.96 with free shipping. (Non-members can spend $49 or more to qualify for free shipping.) That's a $4 overnight drop and the lowest price we've seen. These versatile bowls come in 1-quart, 1-1/2-quart, and 2-1/2-quart sizes with each set.

Note that this item is part of the Amazon "add-on" program and can only be purchased with an order of $25 or more.

Update: The price has increased to $9.37.