Economy for GEO mods
The economy file used by Seasons defines changes in prices and costs over a year to simulate the global economy. For example, for most crops that are harvested in the autumn, the prices drop because of a high supply and lower demand.
Factors, fills, animals, bales
Be careful when changing the values. Changing economy factors changes the whole economy, and thus the gameplay. You might be adding cheats to your game, which would be a pity. For example: if you increase the price of silage bales too much, you might not need to do anything other than making silage because it is way more profitable than anything else.