My package wont be fulfilled by Amazon, so I dont load up AMZ warehouses on something that might be a dud, or undercut by 500 copy cats in 20 seconds.

The package is a large flat envelope (9x12) and the post office can ship it for $1 anywhere in the US.

question 1. When the purchase happens, can Amazon print a mailing label for the buyer in USPS correct font?

question 2. It appears like they offer some kind of shipping rebate. Is that true? Why do they do that? Does it come regardless if I self fulfill and use USPS?

question 3. I cant find training videos that get deeper...maybe I need to create the account first?

Thanks for anyone who helps...