Free Premium Credits via your UPlay account.

[RimBlock]

Check your UPlay.  I had a item to redeem that gave me 170 Premium Credits for zero cost.  

This is as well as the extra 200 for logging in during this week and extra to the initial 170 or so you also get free in game on Premium launch.

 

[DeadSockPuppet]

I'll have to look into that.  I knew about the free 170 credits, I'll have to try and pick up the 200.