Why was I charged a $15 courtesy pay fee??

You will have to ask.the third party company you got.the code from.

i have been selling on ebay for over 10 years,

ebay fees are 10% of final selling price plus listing fees,paypal are between 2%-15% fees depending on final price,the more expensive the item the less percentage you pay.

the buyer pays the price for postage that you state in the listing but most buyers take this in to account when bidding.

if someone is charging £2-£3 to post it you are less likely to get a high price for the item itself as they allow for the extra.

paypal also charge you fees on you post costs too.

MS just want every penny they can get regardless of what their customer wants, if im paying £5 a month for their service i should be able to decide if i wanna watch ads or not. Isnt that why we pay a TV license? As BBC make no money from advertising they
charge a fee, very few services i know require you to pay a fee and have forced ads.

Online fees reminds me of the fees for baggage/blankets/pillows that airlines charge for. They can and they will. Someone will pay it.

This is a day one purchase for me. I don't mind paying the $15 monthly fee.