Amazon offers Prime members the Chef Buddy 20-Piece Glass Bowl Set for $15.26 with free shipping. (Walmart offers it for the same price via pickup.) That's the lowest price we could find by $5, although we saw it for a buck less last month. It includes two 30.5-oz, 17-oz., 11.8-oz., 6.7-oz., and 5-oz. bowls, each with a lid.

Update: Amazon's price has increased; however, Walmart still charges $15.26 via in-store pickup.