Thank u so muchI don't know anything about the value of old saxes. Finding out the year it was made might help. Find the serial number on the sax and look up the year it was made. This link will help.
From what I sometimes read internet, some people buy 'vintage' saxes to play them. Others mainly to 'collect' them.
Thank you so muchThere's more than you ever wanted to know about Boosey and Hawkes here