New 100 Dollar Bills

CSOTUS: Where did you get those figures?

ebay fee is 10% unless you own a store, then it's 6% for currency. ( ebay fees are also capped, but I think that applies to very large dollar amounts before that occurs)
Paypal fee is $0.30 plus 2.9% of the transaction, unless you have micropayments or have had enough money flowing that year to lower fees.

Those are the percentages I have been using in my calculation for a few years, have they changed?

I sell unc 2009 A series hundreds with some regularity usually at $119.99 plus actual postage. If you do decide to list them, be aware that there are tons of fraudsters out there that attempt to buy them. Some will use stolen credit cards, so make sure the name on the shipping address matches the billing address before you ship. So long as you follow the ebay/paypal seller protection rules you will be protected from this type of fraud. The second most common type involving sales like these are people claiming that the packet you sent them was empty or had a lower valued note inside. This type of fraud is hard to prevent, so be sure to insure your package and if you can video tape yourself packaging the note as proof for ebay if a case is opened against you. On average after fees shipping and insurance you can make about $5 per note.

You don't neccesarly have to do a $.99 cent auction. Figure out the fees & shipping and put it up as buy it now with the profit margin your comfortable with.