is there any website or program that allows us to add loyalty reward system in our website for free?

[Mushfik]

[Jake]

Nothing free comes to mind, you could be looking at at least some custom site code that requires people to create an account and keeps a record of their purchases or other activities.

There are many marketing services with the swagbucks sort of approach who recruit a large number of prospects promising them rewards to trying a variety of products and services, really a specialized advertising scheme that can be effective, but you have to pay.