As you already know shipping is more expensive.
I pack 90% of the time with a brand new box, bubble wrap and peanuts.
I will in some cases recycle shipping supplies, but only if it is
scent free and in good shape.
My shipping is calculated with the Ebay shipping system. I usually
offer both USPS and UPS on my items with a few different options for
you to choose from. I always pack very well.
Also if you do not know already the USPS has changed to a dimensional
based weight system for shipping packages for Priority Mail.