In order to accept payments on the internet, you need a merchant account or the equivalent (like PayPal!) You’ll also need a shopping cart if you have a product catalog of any sort and want to be able to do transactions on the internet.
Payment Processing
PayPal 
PayPal performs payment processing for online vendors. This is a great entry option if you aren’t doing a lot of sales. But be aware that you may lose customers who do not trust PayPal.
Shopping Cart
A good shopping cart connects to a large variety of merchant accounts, easily and seamlessly. A GREAT shopping cart will also track customers and potential customers, allows you to setup auto-responders and just makes things easy with a little bit of learning!