There are some online eBay Fee Calculators and Paypal Fee Calculators:

The same author Ryan Olbe built multiple tools for public online trade websites:
1: PPCalc (Paypal Fee Calculator) — ppcalc.com;
2: eBay Fee Calculator
3: Amazon Marketplace Fee Calculator
4: Half.com Fee Calculator
5: ePier Fee Calculator
6: BidPay Fee Calculator
7: Etsy Fee Calculator
8: Overstock Auctions Fee Calculator

Other:
9: PayPal UK eBay Fee Calculator Stores
10: More free eBay Fee Calculator (you can find different Fee Calculators based different countries here)