Payment Gateways allow you to accept credit card payments on your website. They effectively act as the link between the end-user and your bank. If someone buys something from your website, the transaction will get processed by the Payment Gateway, and once approved, the money will be paid over to your personal bank account.
MyGate supports 3D secure and has a monthly fee of about R300.00. Their UI where you withdraw funds is also very easy to use and very slick. I have used MyGate personally and I can speak out of experience that the support is great and it's fairly easy to integrate with a website. You will require a merchant account from your bank to be able to use MyGate.
This is also a a payment gateway I've used. I don't like their interface as much as I like MyGate's interface, but essentially both do what they need to do. Setcom's support is also great. The biggest factor between choosing between Setcom and MyGate would be what the monthly fees are. You would have to discuss fees with them and see what rate you can get. Setcom will also require that you have a merchant account with your bank.
2Checkout.com unfortunately has the highest fees out of all the Payment Gateways on this page. However, Namhost uses them despite this, as they offer very convenient ways to receive payments, including a direct bank transfer without the need of getting a merchant account.
Click here to view the 2Checkout website.