Amazon US interesting thing.
So I took a trip through the free Christmas romance offerings. (Nothing that stands out, just went to Kindle > Romance > Holiday - search "Christmas", sort by price.) Anyway, when all my order confirmations came in for the dozen or so free books, I also got three promotional credits entitling me to selected 99 cent ebooks, one each for Romance, Sci Fi / Fantasy, and Lit Fic.
I would guess getting any book from a genre entitles you to the offer for that genre.
Of course, maybe everyone already knows about this, but I rarely have anything to contribute so thought I'd mention it.
