Amazon’s Flow for iPhone
This pretty much just feels like Google goggles, and even I played with that for a bit and never used it again. The use case mentioned seems plausible, but I also like to think that price is not always the only factor to consider. Immediacy of a purchase can outweight any given “savings”, unless it’s a gift – in which case, an online purchase and direct shipping might make sense.
I often prefer the use case of wanting to find out if the product is “good”, and comparative shopping with other products that do similar things. So many things to consider – this is just scratching the surface.