The above table is valid as soon as you have bought your market stall (and thus have the opportunity to buy and sell resources). Before that only the part saying "produced resources" in the table "Stores" is applicable.
A resource unit takes up 5x5 squares and a store unit takes up 4x4 squares. Since the space you have available is limited it makes sense to calculate income per square on the different units.
The above table will change slightly depending on the market prices on the resources but gives you a rule of thumb on which units to build to optimize your monetary gain :-)
Do take into account that the resources does not need any manual input (as long as your storage is large enough) so if you play less often than every 8 hours it might make sense to build large storagehouses and focus on resources even though they have a lower return per square. I will update the table when I reach higher levels and get to try out more resources/stores.If you want to see the underlying data you could have a look at this table:
For those that wonder how things are calculated:
- Cost (coins) is done by adding the coin cost to the buy price of the resources needed to build something
- Hours to payback is basically how long it will take before "Cost (coins)" is reached in profits
- Value/day/square is profits during 24 hours divided by the number of squares used. (For the store units "produced resources" it also includes the part of resource units needed to produce that specific product.)