I ran a permafree through Fussy Librarian last month and did fairly well. I'm still getting sell-thru and audio sales on it. The one I'm running this month is lagging way behind, although it's a lot longer than the first one and will take longer to read. Since the 2nd and 3rd books are 99c, I did sell four of each of those almost right away. I also don't have an audio for that series so I can't count on it doing nearly as much.
Other than that, I've sold four books through D2D and only one wasn't part of the promo, 9 through Kobo all part of last months promo, 21 on Zon from last months promo, and eight from this month's promo (already mentioned above).
Only one sale this month wasn't part of any paid ads. Pretty pathetic now that I'm looking at it.