Seems like your ideas are generally around finding good deals, price hutning, so my guess is that the YCombinator startup that hired you is around the same idea. There are a few YCombinator startups that deal with simialr things; I don't have the time to find the entire list. Maybe someone else can do that and the HN community can figure out which company did this.
http://www.scatter.fm/ (and a mobile app) - a location based deal site and mobile app for hunting deals from nearby shops.
Or https://yenbe-beta.appspot.com/
Seems like your ideas are generally around finding good deals, price hutning, so my guess is that the YCombinator startup that hired you is around the same idea. There are a few YCombinator startups that deal with simialr things; I don't have the time to find the entire list. Maybe someone else can do that and the HN community can figure out which company did this.