Midlands Sports Auctions, based in West Bromwich, are selling Joe Smith's gold medal from WBA's 1919/1920 title-winning season.
The lot, which is being auctioned online until Sunday, November 28, is described by MSA as "extremely rare".
The lot description said: "Here we have a extremely rare item of West Brom memorabilia, this is the nine carat gold medal awarded to Joe Smith for Albion winning the Div 1 Championship.
"Stamped The Football League to the front; to the reverse West Bromwich Albion FC 1919/1920 J Smith and hallmarked; approximately 29mm diameter weighing 20 grammes."
"This was the first and only time that West Brom were crowned champions of the top league so this in its self makes this a very rare item indeed, added to this the Albion only used 18 players that season so less than 20 of these medals would have been issued.
"Joe held the right back position for the Albion and played in all but two games in 1919/1920, only two team members played more."
Albion won the league following the end of World War One and broke records, topping the table by scoring 104 goals and winning 60 points.
Tim Beddow, from Midlands Sports Auctions, said: "We are really delighted to have this extremely rare medal for sale. Due to Albion only winning the one Division One title it is a real find."
Several other sports lots are under auction including rare Wolves and WBA programmes including one from the 1931 FA Cup semi-final match between Albion and Everton at Old Trafford.
Wolves fans who want a piece of history will be interested in the menu from the civic reception held for the 1957/1958 title winning team. Another programme from Wolves's exploits in Canada in the 1960s is also for sale - the game between Wanderers and the Vancouver All Stars took place in June 1963.
Speedway fans can get their hands on a programme from 1962 from a Cradley Heathens meeting with Poole, complete with the results written in pencil.