Add a "counter to items when they are not posted because minimum price isn't met similar to with expired/cancelled posts.

E.g if an item fails to post X times, it would use the next auction operation or could feed it into a dynamic price system like the below for expires

NormalPrice * (1 - 0.01 * min(max(NumExpires, 0), 33))

Essentially thinking that failing to post would be equal to an expired auction for reasons to cut losses and go with a less optimistic price and/or at a loss