Recently there was a question about things you would still buy even if the price doubled:
It got me wondering about the opposite question, which in my opinion, is much more interesting. What would you buy (that you do not currently buy) if the price came down by half (or was reduced to one tenth)?
Usually products become mainstream when someone comes up with an innovation that significantly reduces the price of something, making it affordable to the masses. Historically, great fortunes have been made this way.