Calculating the BTC

[rabiulawal1971]

I want to determine how many bitcoins to charge someone for some goods.

What is the accepted, fair manner for determining the exchange rate?

For example, right now at mtgox it says: :

[Kravious]

There buyers and sellers in BTC and they usually calculate it via coinmarketcap. For ETH, you could use Coingecko.