Australia Kangaroo £1 Grey, used on parcel fragment - Cat $A4,000 for $A395: Very scarce use. This stamp is SG 137 cat £275=$A550 used OFF piece! ACSC lists it on parcel label or parcel fragment as $4,000. With a “LATE FEE - MELBOURNE” dated cds, most likely on a parcel to the UK, where this piece was for most of its life - bought it off a recent migrant here, who had it is the family collection from before WW2. For the price you’ll pay for a single OFF piece! $A395 (Stock 859JQ)
https://www.glenstephens.com/rarity.html