Why did they sell it at such a high price?
the simple answer.... because they can. The market will bare it.
At this point there are really only 2 options for home miners... Bitmain and SP and Bitmain is less than SP.
The Avalon 4.1s are nice for home miners as well. Just a bit more expensive, but extremely quiet for 1+ TH/s. I have a mixture of Bitmain S3s, S5s, and Avalon 4.1s.
I originally had 9 S3s at my office, but have since brought them home and replaced them with the Avalon 4.1s since they are much quieter and virtually have almost no sound at all since noise is the concern at the office.