I earned about 50 gold boxes today (which I know because the system counts them). The drop rate on the best stuff is pretty low...the boxes are heavily weighted with junk, a few alchemy reagents or siege.

I did get a forward camp and a hakeijo. If I had to guess, based on cost in the game, Zos considers these "purple" rewards, and the drop rate for this category looks like 4-5-%. I'd guess the motifs are considered "gold" rewards, with a drop rate of 0.5-1%. My guess is that this event will make them widely available in guild stores, but won't drop the prices much. So I'd expect the best to stay up around 100k gold, down to 40 maybe for the commons.

If I hated pvp and wanted to get them, I'd use my time to farm other spendy motifs to raise gold for the Akaviri. I can earn $75k in Abahs watch motifs in a couple of hours. Which...if you don't pvp...is way less time than you'll spend trying to earn AP.