About eBay Fees
eBay typically charges a "Final Value Fee" which is a percentage of the total amount of the sale (item price + shipping + sales tax) plus a fixed $0.30 per order.
How to maximize profit
To increase your net profit on eBay, consider offering "Free Shipping" but incorporating the shipping cost into the item price, or becoming a "Top Rated Seller" for a 10% discount on final value fees.