I like the idea. I recently had to buy an adapter for a sound system on very short notice. It wasn't available at Best Buy but it was at a nearby local music store. I got lucky because the Best Buy employee recommended the music store - I wouldn't've thought to look for a music store. Your app would solve this problem (if it had my adapter in its catalog, anyway), but it's a once-a-year problem for me and so I probably won't remember your product's name by the time I need it next year. So, how are you going to get users? Are there certain types of users who will use this more often?