Well, there are still resources to donate, whether it's labor for a sweat lodge, or preparation for ceremonials. Potlatch, Food for meetings and ceremonies, Gifts to shaman would also count, the items found or obtained for medicine bags, sacred herbs, etc.. are all resources though they may not all have price tags.
The sweat lodge as far as I know is built by the Medicine person and those chosen who know the right way to do it. But not all Nations have such a ceremony. Only the people using the lodge are allowed to touch it.
Potlatch is a party.... one where the organizer gives away possesions as a sign that money has no meaning to them. It isn't about paying for religion but a symbol of the uselessness of worldly goods.
No one is requiered to bring anything to a ceremony or gathering.
No one is required to give gifts to a Medicine person (we don't have Shaman) and if someone asks for a gift they arn't a true Medicine person, they are a fraud.
The medicine person gathers all their sacred items on thier own, they are not given to them... what would be the point? They need to have a connection to the things they use that is far deeper than just a gift.
If you ask any Native American who walks in the traditional way for food, they will give you food. If you ask for shelter they will give you shelter. If you tell them you will do a ceremony for them, but you have to give them something in return, they will turn their back on you.
We give because it is the good thing to do, not because we think we will get something in return for it.
No religion (at least in modern terms) to my knowledge requires one to pay to pray. Gifts to a religion are not always money, and they should always be dedicated sacrifice of some kind.
Any religion that asks you give them something (money, labour) is asking you to pay for your spirituality. IMHO
The only sacrifices are personal ones, you sacrifice to yourself and Creator, not the bennifit of a religious organization. Not to keep a 'holy person' from having to work, or to maintain a building or a meeting.
This is just the way our relgion works.
wa:do