After trying to check with Mr. Google, I have bumped into this website: Link hidden: Login to viewNote: This website is not an affiliate or not connected with SaleHoo so please use at your own risk
It has a very simple interface and looking at it face value would only entail that it is does not give any accurate figures however, a rough estimate would be as much help compared to none. Please do note though that they only have Euros for the currency so you will have to do conversions.
If you are after the fees charged by eBay or Amazon, you can check on the links below. Generally, do remember though that eBay usually charges for listing fees and final value fees (excluding Paypal fees) rated at around 10% while Amazon charges on variable closing fees and referral fees ranging from 8%-45% depending on the product category. This can help you determine a rough estimate in pricing your products and to find out the best e-Commerce platform for you.Link hidden: Login to viewLink hidden: Login to view
Hope this helps!