A Gypsy promise
"Cross my palm with silver and I'll tell your fortune. Cross my palm with gold and it will certainly come to be. Cross my palm with iron and you won't live to see daybreak.”
Back in the day coins were made with precious metal. Cross my palm just means 'place in my palm'
I was once told, but have never seen this anywhere else, that it used to be when you had your fortune told you would pay in silver and place the coins in the shape of a cross on the fortune tellers hand. This was to ensure that the fortune teller was not working for the devil.
Far older than that, crosses of various kinds were pagan symbols, crossroads were of special significance and the crossing the palm with silver would guide the reader to give the right reading
The cross also represented the holy tree on which the green man/ Sun god/ chose male deity as you wish was hanged. Upside down if the tarot designers are to be believed but there are references that pre date the tarot.
Hazlinny, when my children were tiny babies strangers thought it acceptable to put a coin in their hands. Those were the days when strangers thought it fine to podge a baby or stick a filthy finger in their mouth, but they survived