there are several sites that give this - try google, there is also a table published in David Kermode's 'offshore island politics' that gives historical retail price index 1900-2000;
note however that way of life has changed immensely (eg what was the 1850 price of an mp3 player?) - the 6d was a purely nominal amount dating from the 16th century (when it was worth something) that was the minimum you had to leave a child otherwise the ecclesiatical court stepped in (see manxnotebook under wills etc for some history) - usually sign in later wills that a child had already had a marriage settlement