Pay to surf is when people are paid money to use a special program that shows them advertisements while they use the internet. This kind of program can be installed on computers or mobile devices.
So, let's imagine you're watching some pictures online, and you have this application on your device. You can use it to see advertisements, videos, and other things while you surf the internet – and, in exchange, the company that created the app will pay you a certain amount of money for your time.
Basically, it's like getting paid to watch commercials instead of just ignoring them or clicking them away. It's a way for advertisers to get people to pay attention to their deals and promotions, and it's also a way for people to make some extra income for just surfing the net.