You can actually do about 200MH/s on the LX150-N3, and if you order bulk quantities of that one (100pcs) you'll get it for as low as $115. That's almost 2 MH/$, so almost on par with GPUs. But you'll have to consider the cost of the board, other components, assembly, and time spent on it as well.
Destroying a $40 part is about as high as I'd want to go. And if I destroyed the first one I may not try another.