The best place to check any coin valuation, apart from seeing a numismatist in person, is to check on various coin valuation websites such as Jake’s Marketplace (jakesmp.com) or mycoincollecting.com. Internet auction sites are full of amateur numismatists so, having checked the calibre of their selling history, it might be worth putting the coin on one of these sites before seeking a professional valuation. Indeed, the more research you do yourself the better the amateur numismatist you become in addition to this. The price also depends on the condition of the coin. Unfortunately, it is likely the coin is a fraud, since no silver liberty dollars were made until 1836. The Mint had problems during 1798 and 1799. Hygiene in Philadelphia was inferior to what we expect today. Yellow Fever raged in the city during the summer of both years, shutting down the Mint and sending all citizens that could afford to leave to head for the country while the poorer inhabitants were forced to stay and face the plague. Considering the confusion surrounding the disease and the inconsistent periods during the summer when the Mint was open, it shouldn’t come as a surprise that dies were taken at random to be used in coining machines rather than in the usual orderly manner. Trying to follow die progressions and die matches can be difficult for this reason, as dies were sometimes taken out of turn for use in striking coins. The coin on this page is easy to recognise as a forgery as there are liberty seated trade dollars made in the year 1799. Liberty seated silver dollars were made from the year 1836 until 1873. Trade dollars were made from the year 1873 until 1885.
