There are several elements involved when it comes to building a successful online business, from crafting your offer to having the right platform to marketing. Once subject that is critical to the success of a business is the subject of payment processing. 

All you have to do is choose the program or programs best suited to you:

• PayPal: is widely used and respected as a payment processing option, which allows buyers to select various funding sources such as a bank account or even credit cards;
• Sage Pay: enables thousands of businesses to accept payments on the internet, by phone, fax or mail. Credit and debit cards, bank transfers, instalments, even mobile payments;
• 2CheckOut: is a payment processor which is a combination of a merchant account and payment gateway that doesn't require a PayPal or a Merchant account;
• Stripe: this prevents the need for a merchant account, and also allows you to build your own payment forms that can bypass PCI requirements;
• ACH Payments: being able to make global payments, as well as serving as a payment gateway, merchant account, credit card processor, and mobile payment processor;
• Google Checkout: allows users to pay for goods and services through an account connected to their Google profile. 

There are plenty of online payment systems out there that you can use, we would recommend choosing one that's in line with your business objectives.