Why do people advertise to show you how to do something and then direct you to pay first?

[theREDdragon]

[058]

Because we live in a day and age when people are money hungry.

[786]

Often it's just a scam.
Otherwise it's because we live in a world where so many people don't pay their dues.

[Khuzaima]

This is very simple and clear. They do just to attract the online viewers. This is an internet marketing strategy, that's all. On the first site people get interested by looking the product's glamour and then move a step forward to use that then suddenly a notice comes in front of them to pay. If the viewer needs that product , then he/she will definitely buy it. If not, then they will leave the page.
This is totally a game of chance from internet marketers.