Fair trade prices. The base amount is the complexity involved in producing. For example iron, wood and water is produced by buildings that have no requirement so a factor of 1 multiplied by 100 coins. A cookie has components to to value of 43 plus 1 to make 44 multiplied by 100. Biennaly food requires an upgraded feed depot so to recover the cost of building plus the water to produce multiplied by 100. The minimum is half what it cost in time and components to produce.  The maximum is three times the cost of producing.

Produce	Factor	min	base	max
Water	1	50	100	300
Apple	2	100	200	600
Cookie	47	2200	4700	13200
Carrot	3	150	300	900
glue	3	150	300	900
Grain	4	200	400	1200
iron	1	50	100	300
milk	14	700	1400	4200
wool	6	300	600	1800
Sugar	14	650	1400	3900
leather	7.5	375	750	2250
Thread	2.5	125	250	750
wood	1	50	100	300
Monthly	2	100	200	600
Quarterly	4.46	150	446	1300
Semiannually	7.34	300	734	2200
Annually	10.68	500	1068	3300
Biennially	14.48	700	1448	4500
Credit	80	4000	8000	16000