Here is a real life example.
I listed an obsolete $5 Las Vegas Club chip on Ebay. I started the auction at $5 which is exactly what I paid for the chip when I purchased it from the cage a few years ago. The item received one lone bid for $5.
The breakdown.

Cost of goods sold: $5.00
Ebay insertion fee: 35¢
Ebay final value fee: 44¢
Paypal fee: 51¢
Cost of bubble mailer: 10¢
First class USPS postage: $1.17
Total costs: $7.57
Total revenue: $7.25 ($5.00 + $2.25 shipping)
It cost me 32¢ for the pleasure of scanning, listing, tracking, sending an invoice, leaving feedback, packaging the chip, driving to the post office and standing in line.
I am NOT complaining. I chose to list the chip at $5 and I chose to only charge $2.25 shipping. That's the chance I took. Of course not all auctions end with only one bid and of course I don't take a loss on every auction.
The purpose of this post is to criticize (and possibly ridicule) those who rail against anyone who charges anything over $1.00 for postage. If you don't like the shipping charge, simply don't bid. It IS that simple.
AND if you choose to bid on an auction that has a shipping charge of $2.25 (or more)and you win that auction, don't get all passive/aggressive and ding the seller on the detailed seller ratings. YOU chose to bid on the chip knowing full well what the shipping charge would be. If you don't like the shipping charge, go bid on an auction that has free shipping (and quite likely a higher minimum bid)and leave me alone.
My next batch of auctions are likely to have a shipping/handling charge of $2.50 instead of the $2.25 I have been charging.