Originally Posted by JDiver
Welcome to FT!
In one simple word, "no."
However, you can buy someone else an award with your miles...
In one simple word, "yes".
The OP asked if it were "legal".
I am not aware of anywhere it is illegal to sell miles.
It violates that terms of your FF program to buy or sell miles, and that could cause you significant problems. However, the government isn't going to fine you or put you in jail for it.