Starting with the ubiquitous "I looked for this and couldn't find it so..."
I checked my Power Up rewards account and there was an Active Offer of a $10 off coupon with no restrictions. This was without using any points...just a free$10 that showed up one day. Wish I had more details on the why, and the when. I know it expires near the end of February.
Not sure if it was just me, or just some accounts...but check your active offers.
I used mine tonight for a free $10 PSN points card.