I give you a piano lesson.
You dog sit for someone.
That person bakes cookies for a shut in.
A person drives someone to a doctor's appointment.
Someone else baby sits for a few hours.
Someone repairs a leaky faucet.
A woman offers a dance class twice a week.
A glazier replaces a window.
Someone changes oil.
Someone donates an hour of house cleaning.
A farmer offers a day of horseback riding.
All those services, regardless of time or skill, are worth a single point and don't cost the recipient anything unless there are materials needed such as plumbing or carpentry. Each church would have to tweak or limit time intensive events like building a deck.
Everyone banks their points and is able to redeem them from anyone who enrolls in the program. This may or may not be applicable to regular liturgical, church or service to the church activities such as coffee hour, ushering, cleaning, donating flowers, etcetera. It would work best between people rather than "the church" unless you want to include service to the church as a service to the community. YMMV.
A program such as this would greatly serve the poor but could tax the handyman (who would gain mega points, though) and everyone could list what they are willing to offer in services and limitations. There are two ways to promote service. A church can have its members make a list of services they are willing to offer and someone with a need can check the list and contact that person. The other way is to allow people to list their wants and a provider can contact them to offer that service. Both lists would work very well simultaneously.
Each individual church would need to tweak their own by-laws and perform a few months of dry runs followed by circadian by-law updates to fix bugs, disadvantages and services offered. It could be maintained online, in a book or by an individual. The organizer could create a formal receipt which will be turned in to them who then updates the points. This is not a barter from person to person but to the community.
If I only offer piano lessons and nobody takes me up on that, I will bank no points so it would behoove me to offer other services such as house sitting, shoveling snow or dog walking. And of course, I can't offer plumbing services if there is no proof that I know anything about plumbing (although I do do my own).
So If I give you a piano lesson and earn a credit, I don't have to barter specifically with you in return for a service. I can use that credit to take a dance lesson or have someone clean my house and they in return don't have to barter with me. The bylaws can be tweaked in a myriad of ways such as, one is able to give their credits to another person or a certain service is worth two credits. Maybe there would be a limit on how many credits you may give or receive each week.
Ultimately this program would work best if nobody puts a value on their service and looks simply to serve. It would be a great opportunity for a congregation to build community, serve one another and be Christ for one another.