Upkeep will be governed by the following rules:-
1. The base unit for upkeep is an infantry unit, at 10S per turn
2. When a unit levels it adds half its base upkeep, for example a level 9 piker = (10 + 5*8) = 50 schmuckers per turn
3. Warlords upkeep is 10 times that of an equivalent levelled unit, for example Jillian, a level 9 warlord (10+5*8)*10 = 500 schmuckers per turn
4. Special abilites such as Heavy, Flying etc can be added to a unit for an increase in upkeep.
5. If you have provisions, upkeep is reduced by 70% rounded up.
As stated elsewhere in canon, a warlords purse is level * 1000.
Upkeep per Turn Formula
Schmuckers per Turn = B*(1 + (L-1)/2)*W
Where B is the Base Unit Upkeep - the amount for a level 1 unit of that type. L is their level, and W is 10 if they are a warlord, 1 otherwise.