Money might be one of the hardest things to share (maybe after your toothbrush), because it is a medium of exchange and the concept of the exchange is to ask for what you get in return before you give something - quid pro quo. There are very simple schemes you can make to voluntarily share money-resources.
Sharing money is often usual in communities, through a common bank-account for example. Volunteer income-sharing is another way to share money.
By sharing goods, ideas, skills and services you can reduce the use of money.
A good way to share money is to not directly share money but to share expenses. This can happen on donation basis according to your personal contribution - as for example with the concept of the magic hat of the rainbow people.