Thanks for the offer.  I might take you up on it later but right now I'm saving up to purchase more Android Tablets (e.g. http://www.gadgetsdealer.com/product126439.html) to take around to more stores.  I want the barrier of entry to be zero for the merchants so I'm going to loan the tablets out for free for the time being and probably do some sort of rent-to-own arrangement later on.