To earn money with affiliate marketing, you first have know what affiliate marketing means.
Affiliate marketing is a type of digital marketing where you have to promote products of others and they will give you some percent of their product's price if product is sold.
Usually you get 3% to 15% of product price for selling their product, but some times it's higher than that if the product is digital product.
To earn money from affiliate marketing you must have audience, and that audience can be your website visitors, YouTube subscribers, your Facebook page followers, your big friend list, etc.
If you have any of audience mentioned above, then you are good to go.
Now, you have to join any Affiliate program you like. Many companies like Amazon, Flipkart, Snapdeal, Clickbank, etc. runs their affiliate programs to promote their products. You can join them they are free, and then start promoting their products.
Once any of the product is sold from your affiliate link, you will receive your earning in corresponding account.
For example, if you are working with Amazon affiliate program and you make sell for them, then you will receive your earning in your amazon affiliate account. "Mens Dose" is best example of affiliate marketing website, here all products have purchase links which are affiliated links.
Earning process of affiliate marketing works in 6 major steps:
Lets take a real life example,
Sam is promoting a TV of amazon and cost of TV is around Rs.50,000/-. The affiliate percentage for that TV is 5% of its cost. Then for every sell Sam makes through his affiliated link he will get Rs.2000/- in his amazon account. If he have a good amount of audience, he can sell minimum 2 TV in a day and make profit of Rs.4000/- every day without any investment.
Affiliate marketing is free to use and many people are earning from this. Some of the people are even spending money to advertise their posts of affiliated products and earning from it.
If you have decent amount of audience then yes, why not? You can give it a try.