The ultra-rare 25p coin looks very similar to the ordinary UK 20p piece.RWB AuctionsA rare coin found in a man's change is estimated to be worth nearly $1,000 at auction.The coin looks a lot like an ordinary UK 20p piece, which would be worth about 35 cents.But it's actually an extremely rare experimental 25p coin minted in 1981.A man was handed a nondescript coin as part of his change while buying lunch.