I'm by no means an expert but I know a lot of people have misconceptions about what second hand rugs are worth. In "as-new" condition, never been on a floor or walked over, it may have some value but if it's been used it's worth nowhere near what you think. It isn't a rare antique, only the rare, old orientals hold or appreciate in value.
If it's in a very nice condition a rug dealer may offer you something for it, if they thought they could sell it on for a profit, but they wouldn't offer you much I don't think. Maybe you'd get a couple of hundred quid on eBay if you stuck it out for the right bidder.
Having said all that, there's one born every minute so you may get lucky and find someone willing to rip themselves off for the pleasure of owning it!