A simple model of a basic economy
Consider a household which owns an apple orchard and that decides to go into business. They hire workers to expand the orchard, look after
the trees, pick and sell the crop.
The household needs to pay the workers, and to do so they engage the services of a friends who have a
Monopoly set.
The friends set aside
M 100 of Monopoly notes and put them into a piggy bank: this will be the source of all funds for the basic
economy  no more notes will be added nor subtracted. These friends call themselves "The Bank".
The Bank agrees to supply notes to the Orchard Firm at an interest rate of 5% per annum (5% pa).
The Bank in fact sets up two piggy banks  the one that holds the original bank notes (The Vault), and another to manage moneys
coming from interest payments (Bank Assets).
The Firm sets up two piggy banks  one to hold the loan from The Bank, the other to manage moneys coming from the sales of
apples (Firm Deposit Account).
The Workers set up one piggy bank (Workers Deposit Account) to receive payment for their work.
The parameters of the model are shown here:
Bank Vault starting value 
M 100 
Bank Vault lend rate 
75% of Vault balance pa 
Loan repayment rate 
2% of Firm's assets pa 
Workers payment rate 
200% of Firm's assets pa 
Workers spend rate 
26 x 100% of Workers savings pa 
Bank spend rate 
100% of Bank Assets pa 
(M is the (Monopoly) monetary unit of account; pa = per annum)
To explain these parameters:

The Bank Vault holds only M 100 of notes and no more. To formulate a dynamic model, we need to choose a rate at which The Bank
lends out notes in such a way that the Vault is never overdrawn. This model takes the rate of lending to be 75% of the current Vault balance per annum.
Over time, other things being equal, this would give an ever decaying balance tending to zero.

The Firm repays the Bank loan at a rate of 2% pa of its total assets (loan plus income)

The Firm pays wages at a rate of 200% pa of its total assets (loan plus income). At first sight, this may seem impossible, but remember
that this is a flow (amount per unit time) rather than a stock.

Workers spend their entire paycheck every 2 weeks.

The Banks spends its entire income each year.
Using Steve Keen's program
Minsky, the above model can be simulated over time
(
Click on image on the right).
Download Minsky source for this model:
Download link (rename to remove [.txt]).
A more full explanation together with the equations of this model is here:
Model equations
Initial values grow or decay until a steady state is reached after approximately 6 years.
The final (steady state) values are shown below (values in
M)