One day you've never heard of Frank Reenskaug; the next, his teak rocking chairs from 1958 are everywhere. But even then, you can't find out much more than that a handful of chairs are for sale [or sold.]
Good Eye, a 20th century design store in DC, just put one [above] of Reenskaug's Model 182 rockers in their eBay store. They supplied the 1958 date, and they have the lowest price: $595, plus $65-75 to ship [local pickup is free.]
Modern Times Chicago, meanwhile, identifies Bramin as the manufacturer a Model 182 with new webbing for $999 plus your own shipping [or local pickup].
Both Modcats and Surfing Cowboys have Reenskaug rocking chairs in their "sold" archives. But the only price history I can find is from Rago Sollo's auction just last week, where a Reenskaug rocker which was estimated to go for $2,000-4,000 sold for a pretty decent $2082 [$1700 + 22.5% premium] to a live bidder.
Before you quit your job to get into the mad-money world of rocker flipping, remember that price could be a total fluke, the result of two competitive schmos, who didn't mind overpaying--or a single schmo who got strung along until he reached the reserve price.
Of course, if you've got some time before your due date, you could just sit back to see if one turns up on Craigslist for $15.