My favorite solution to all of this has been to use a bulk rate shipping service called Rollo. I discovered it about a year ago, and it has saved me / buyers of my used gear hundreds. It’s a startup that negotiated a bulk rate with USPS and UPS and they make money by keeping a small fraction, and passing the bulk of the savings onto consumers. No monthly fee or anything. I regularly save 20-40% off the retail rate, and it is a bonus that the user interface is miles better than the UPS and USPS.
Shipping costs- WTF
I just need to vent. A couple days ago I tried to ship some Target speaker stands from Oregon to Ohio. I bought them from a guy in NJ and he paid $60 to ship them FedEx ground. Using the exact same box and packing materials I went to FedEx and they said to ship them to OH would be $170. So I went to UPS: $169. I went to the USPS: $180. Granted it's a large box (30" x 17" x 17") but weight was about 15 pounds and it's easy to handle. So yesterday I took the stands to the UPS store to get an estimate on them boxing them separately. $33 x 2 for the boxes and $104 x 2 for shipping. So $274. For $200 speaker stands. Obviously I'll only be able to sell them locally....