There once was a very expensive VPN client called VPN Tracker 5.2 Pro.
It had a younger brother called VPN Tracker 4 Personal that lived at Amazon.
Their parents would do a cross-upgrade so that buying the little brother from Amazon and upgrading him was signifigantly cheaper than buying the big brother himself.
Five days of waiting, and little brother arrives. In a box sealed with scotch tape, and a serial number that claims to already be registered. Amazon says this was the last one they had in the whole wide world.
Five days of waiting, to save a few bucks, and I still paid full price.