Just my 2¢ worth. If you run a business that ships item on a regular basis you will understand,
I ship UPS & USPS. USPS small & medium flat rate boxes work well for me for items that I know will "fit". They cost $10.20 & $17.10 respectively. I charge $11 & $18 & drive 4 blocks to the post office, mainly trying to save the customer $ versus shipping UPS. Anything I ship UPS incurs a $5 "handling fee" per shipment whether 1 or 3 packages. That is to recover costs of boxes I purchase, tape, staples, the weekly $16 fee that UPS charges to come by and possibly some of the 2.7-3% fee that my credit card processor takes out of every sale.
I hear what you are saying, I don't like paying shipping costs either. All the places offer FREE shipping, it's not free, you are paying for that, it's just not a line item on your invoice. I plugged a 1# package, going 10 miles down the road into UPS. To a residence was $15.66, to a business was $11.62, why the $4.04 difference. You think UPS is expensive now, wait until they all get air conditioned trucks! Not saying they don't deserve such, just saying. I told my pickup driver in the afternoon that he better take a garden hose to himself when he gets home, he is that dirty/dusty.
When I order small items I ask if they offer USPS to save on shipping costs. Not wanting to offend anyone, just stating facts.
Jeff