Sold a couple of shotguns on GB. Boxed the last one up today to ship out a youth model 870 20 ga. Pack it up good and double box it. Plug in the dimensions into the online shipping program. Package was 50x14x4 and ground was going to be $38! So I knew I had some wiggle room and I punched in 48". The price dropped to $19.83!
$18 for one extra inch!!! So if you ship something pay attention to the size, it could save you money.

also check the speed, slowest is not always cheapest.

When working at the grand in Sparta IL, we realized if we shipped to ourselves via overnight it would always show up with the 8am deliveries because the driver was not going to be sent out there twice.

Often shipping companies and airlines have a dimension cutoff before classifying something as oversize. As I recall, it is typically a single number which is the circumference along the long axis; so the two long sides plus the ends.