I got one of these from previous deal from these guys at $13.40 and now it's $9.40 - real bargain for a solid case!
They also have a plastic ABS one at for $6.71 at:
https://www.lightinthebox.com/abs-case-box-for-raspberry-pi-…
This the sensor kit too!
https://www.lightinthebox.com/diy-16-in-1-sensor-module-kit-…
[Edit] - I just checked out with a few on these on the cart and the 'free postage' option is greyed out for 'a better customer experience' (BS) - I was only able to selecte postage with tracking which is a bit cheeky! Bought it anyways…
What does the sensor kit do?