I doubt it'll work very successfully. Who knows, maybe the response from retailers will work...

1. Stores will have to be proactive and look and monitor these deals on a daily basis. This is your biggest risk factor. The reason why Groupon/Social Buy works is the ability to create deals for users instead of the other way around.

2. Quality of the deal is dependent on the user and their desire to get the highest percentage off. Most users are going to optimize for their own best outcome and thus be disappointed when their 80% off coupon does not get through.

3. Once a retailer does a deal at 50% off or higher, it's going to set the bar at that level for other consumers expecting the same or better deal the next time it comes around.