Clever solution - technically. For trips with my friends we use a "money-pot" system where everyone pays a fixed amount into a pot before the trip and everyth

Clever solution - technically. For trips with my friends we use a "money-pot" system where everyone pays a fixed amount into a pot before the trip and everything we do or buy together is paid out of this pot. After the trip the calculation is much easier - refund = (remaining amount / persons) ;-)