$10 business card holder
So when you found the product you were looking for, was it in the sort of store that would be well served spending $$$$ to build a searchable/indexable website version of their catalog/inventory, to have someone create (and keep current!) a Facebook page, and to research Google Search & Maps and Bing and make sure that Sally's Stationary Store comes up right alongside Staples and Office Depot? That would get Sally what, the pleasure of knowing you didn't have to go too far out of your way to bring them your $10? There's money to be made giving Sally that hip feeling sure, but you could just sell her some wacky waving inflatable arm flailing tube men to put on the roof and get Sally a similar result, quite possibly even more people would notice.