the RIGHT buyer might give you $650, if they are looking to add on to an existing set, or get a hankering for some of the older sets
repost pestering just weakens your leverage because it announces lack of interest
i once sold a Vistalite floor tom for good money (after 2 months) and the buyer told me he'd been eyeing it for weeks and was worried someone was going to snap it up before he could raise the funds
in that case, the "mystery" played to my advantage, and i got full asking price... and kept the local listings free of clutter