difference between mini210 and mini210s and tiny210

Hi
What's the difference between mini210 and mini210s and tiny210? 
Why mini210s is cheaper ?
A Chinese seller in aliexpress sells mini210s for 140$. Is it trustable?

Mini210 have stop selling.
For the mini210s and tiny210 Different, please see the follow website:
http://armdevs.com/doc/fa210/info256.html

And notice:  we can provide the user manual in English.