What sort of coin do you want? Big, small, high grade, lower grade (I'm assuming grade has to be reasonable), Henry VII, Henry VIII, Edward VI, Mary or Elizabeth 1? I'm not going to ask whether it is gold or silver, as the former is out of the question in your price range.
Affordable denominations are shillings down to farthings ( shilling, sixpence, groat, threepence, twopence, threehalfpence, penny, threefarthings, halfpenny, farthing) but not for all reigns. There are some serious rarities within that group.