The most valuable piece of football history is an original FA Cup, one of four produced for the first competition held in 1871 and presented to the winning team between 1896 and 1910. An anonymous telephone bidder bought the cup for £420,000 ($773,136) from Christie's, UK on 19 May 2005.
With the added premium the actual price paid was £478,400 ($880,639). Source as attached
Comments below may relate to previous holders of this record.