Free deals
Some deals on a daily-deal site have a really low cost to get as many people as possible to buy coupons. It is even possible to run a free "deal", that is a deal with zero cost. When the deal price is zero, the Getsocio engine will not even ask for credit card and just will give a coupon to any user who clicks "Buy" button.
Running a free deal could be a great way to promote a new business. Sure it has drawbacks, as people will clearly see that it is an advertisement rather than a real deal, and will be more cautious.