These sites are not about generating lots of new revenue; in fact, plenty of business owners from across the country even say they have lost money because of the heavy discounts or commission required to participate. For example, Groupon will ask for at least a 50% discount.
However, working with third party agencies can expose your business to a whole new world of potential customers and give you a marketing reach that you could not afford on your own. It can create a buzz around your business and get it noticed.
For small businesses, these agencies offer several advantages over traditional advertising. It's free to feature your business on the site. With traditional advertising, a business pays lots of money up front with no guarantee that the message will reach the consumers and translate into sales. Also, with tens of thousands of subscribers, they offer free access to the inboxes of target customers.
Once you have attracted new customers, you have the chance to sell other products and add-ons, as well as entice them to come back again and again. You must have a long term view and make it work for you.