Groupon offers the 4-Piece German Mixing Bowl Set in Stainless Steel for $15.99. Coupon code "VISA5" drops it to $15.19. With $3.99 for shipping, that's the lowest total price we could find by $6. It includes a 1-quart, 1.5-quart, 3-quart, and 5-quart bowl.

It also comes in copper or stainless steel silicone base for $18.04 after the above coupon or copper silicone base for $20.89.