I have spent $10 each month for the last 3 months. I see a jump in my views, but no spike in sales. That could just be my product. It's a shotgun approach to marketing, you hit a large population, but many are not interested once they take a look. However, as far as advertising goes, it is pretty cheap. With most shops, one sale would pay for the week-long Search. I think it is a decent value and will keep one Search a month in my marketing budget as part of a larger mix of efforts.
Dave