http://pages.ebay.com/promo/holiday06/ 15 cents per listing for most categories (unless you are trying to sell your favorite tractor). Today only, hurry!
There is no limit on the number of listings, as far as I know. And regarding how often they do it, it's not twice a month, because if it was twice a month, no one would want to list their products on the other days.
yeah I definitely took advantage of this regular fees for me are anywhere from 1.20-2.40 + add ons....I wish the day wasnt over