I have just visited the site you quoted. It needs a lot of technology changes and creative appearance to meet your aim.
As a person who does online shopping for various products, and who is also searching for cashback/discount coupons or deals from various websites, I can suggest some general points from the eyes of a user.
How to reach your site? Now I have visited your site only because you mentioned it in this question. Otherwise, what will lead the user searcher to your site? Here you have to market it through social media or by auto links. You may try to have some affiliate links with some major online sales sites.
When I want to buy a product online I search for its online availability by doing the keyword search. Eg: That result throws the various, Paytm, etc only come. Sometimes I get some new sites which I have not known earlier. As I have some experience I avoid certain sites. Then I search and make comparisons by comparing price an also the user reviews.
Most major sites display the offers and discounts on their web site itself. But sometime there may be some promo codes which may not have been displayed on the website or we cannot easily find. So I search the coupons and deals sites. From my experience, I have shortlisted a few sites. I apply the codes or deals from them. Some sites are well updated and can rely on them.
Some coupons and promo code websites take us directly to the shopping site. Some just give the coupon code or deals with the terms and conditions.
So regarding your website, it needs to be visible on a user's search. It has t come visible on a user's search for coupon sites also. You may review the number of hits you already have and take appropriate decisions and changes.
You need to market your site on social media and other blog sites. But at the same time, you should ensure that what you give is true, working and updated. The visitors should come back.
I remember that the ISC group had started a Deals and Coupons site a few years ago. I am not sure what the status is now.
Now many sites which were giving attractive discounts, cash backs and deals have tapered and even stopped many such benefits.