50-75 bucks for a bare manifold at a swapmeet is probably about right.I've never paid any more than $25, but that's only because when I see them for less than 25, I buy it just because I know that I'll have it when I need it.I usually have one or two at any given time to choose from.Lordco here, just had an Edlebrock on sale for $125 and Holley 600 cfms for $230, so I bought the 600cfm /polished/elec choke for $242.
Lothar