On the advice of a fellow California Writers Club member who has had experience promoting and selling his books on the site, I went to EreaderNewsToday and applied to promote The Year of the Rat there.
ENT exhibits a sliding scale, that I found affordable, of their fees for each genre; my fellow member did very well selling his books at the fees he paid.
This is more or less how it works: You apply using their form, enter all the information about your book, and ask for a date to start the promotion, which usually runs 30 days. Pricing is very low — I set 99 cents for Rat — and one day before the promotion at ENT starts you lower the price at all the online retailers where that book is posted, and keep it there for three or more days.
I asked to start on January 15. They haven’t replied yet, but I look forward to it. There are so many other promotional marketing sites, one very expensive but effective, I am told.