Thumb Score: +19

Amazon [amazon.com] has 1-lb Gardner Bender DS-110N Duct Seal Compound for $2.49 – $0.27 when you ‘clip’ the coupon on product page = $2.22.
Shipping is free with Prime or on $35+ orders.

Savings
Coupon price $2.22 (check and activate [amazon.com])