As a buyer, you're probably wondering why Sellers charge a Handling Fee on top of the Shipping Charge. Well, let me explain what the $1.00 Handling Fee goes to.

Bubble Wrap - A box of Bubble Wrap 12" x 50" is $13.36.  I use at least two sheets of it to wrap each item. 
 
Shipping Label Sticker - Did you know that the shipping labels cost $39.99 for only 100 of them?  That's 39 cents for the label that is on each package.  

Packaging Tape - Costs $1.09 for one roll.  I use it to tape up the box on the top and the bottom, on the packaging label and for extra protection on the bubble wrap.
 
Newspaper - I get the Star Tribune Sunday paper, it costs $26.65 for 3 months of service.  That paper is used as stuffing in each box to keep the item from slipping, preventing damage to your item. 

Shipping Boxes - Depending on the size, they run about  77 cents, 97 cents, 1.37 or more per box. Priority Mail boxes are free but only if the package is sent Priority.

Bubble Mailers - A box (25) of 10X15 Mailers is $9.63 - one mailer is 39 cents.  A box (25) of 8.5X11 Mailers is $6.44 - one mailer is 25 cents.

Delivery Confirmation - In order for your package to be tracked through USPS, a delivery confirmation has to be purchased - it is 18 cents if using PayPal or 75 cents at the post office.  If the item was sent Priority, its free. 

Thank You Note -  When I remember, I place a thank you note inside the package that I make myself.  Cutting the cardstock into small squares and rubber stamping an image onto each square.  I personalize each note.  The cardstock is 25 cents per sheet, the ink is about $3.00, my time is priceless. 

So, next time when you're filling in the dots for the Detailed Seller Ratings (DSRs), maybe you will understand why Sellers have to charge a handling fee of 50 cents or $1.00 on top of the shipping charges.