Drone "toys" are not cheap but they are a magnitude more affordable than the non-toy versions. I got in on the AR Drone "toy" bandwagon a bit early*. It's dropped to less than half price in that time whilst actually having been improved (higher quality video, better altitude sensors, longer range, etc). I expect that the "toy" will drop in price as well like the AR Drone, smart phones, and the like. I also expect the price will hit a floor at around ⅓ to ½ the current price. There is only so much cheaper you can source the components & build something before you kill the qualities that make it desirable in the first place.
That said, I reckon I might look into one of these in the coming years. My wife has (mild) asthma & a fear of confined spaces, making diving an issue for her. It would be kind of cool to "have her along" when I go under. Though, if I wait too long, I'll lose my excuse it's "for the kids"... which was the excuse for my other drone
* Back in 2011, but seriously, as much as folks like to talk about it as a toy, it really isn't much different from "work" drones. Parrot sells it as a toy because that's how you get people to people buy it in numbers, but it's not huge step down from other entry model work drones in regards to design & functionality. You only need minor modifications make it very interesting for computer nerds such as myself