Most online retailers won't use the most economical shipping methods if they can't be tracked. Due to the amount of fraud online, retailers need to use shipping methods that can actually verify delivery (with signature or delivery confirmation).
Also, the shipping carrier will determine price and minimum shipping charge. While those seals could probably be mailed for $2 in an oversize envelope (and certainly could go for the $5 priority mail minimum), if the store uses UPS or FedEx ground exclusively, a residential delivery can easily cost $7-8. Then add the cost of the box and packing materials (or approximates for averages) of $1-$2, labor for picking and packing, e-mail confirmations, figure about $1-2 there, and then you are at $9-$12.
Not sure if that's what's going on here, but high shipping charges can certainly can be explained in some cases.