What credit cards will my business be able to accept?

I have a small business and want to increase credibility, customer convenience on sales by accepting credit cards. Statistics say accepting credit cards can increase sales by 30 to 100% .What credit cards will my business be able to accept?

I say check the ones that do not charge you a fee for taking accepting them from your customers. I have heard that some places refuse certain credit cards because they charge the business fees in order to process them…check the ones I have listed below…
Discover
Visa
Mastercard
I heard American Express is one that charges fees…I do not carry that card.