Amazon with Genicook Product has the GC GENICOOK Store 20-Piece Glass Food Storage Container Set w/ Lids (Grey, GE201) for $36 - 20% off (Clip coupon to apply) - $7 with coupon code 2014NZ76 [Exp 5/7] = $21 with free shipping on $35+ or with Prime.

The 18-piece set is also $21 with the coupon and code.