One cool feature of AACW is that most of your conscript points (meaning any men sent into service including volunteers) are not generated from a given income by your cities.
As most of you know, men enlisting in American Civil War regiments fluctuated wildly. Volunteers responded to the calls, massively at first (On to Richmond!) and when the true horror of the war (simulated by a fall of your National Morale) became apparent, the Union and Confederate governements had to switch to more drastic measures such as paying a bounty to people and even introducing conscription.
This is simulated (but abstracted a bit as you act at the national level, not state by state) by the Drafting Options page of the Ledger. You have several sets of choices.
First, the volunteers. You can get conscripts for free by issuing a call to arms, every 6 months. You can only expect to have a significant number of men if your morale is very high. The good thing is that it costs you nothing.
An alternate solution is that you can give a bounty to incentivise men to join the ranks. You have here 3 levels of bounty possible, costing more and more money but bringing more conscripts into your army. These solutions don't appeal much to people but are still bearable for most of them so you will suffer a light penalty in National Morale.
Finally, conscription. Full or partial. Here you will get a massive number of men (depending on historical census), and don't have to pay anything in money. But in introducing conscription you are basically saying to the population that the war is not exactly going as you expected. Therefore you will have to pay a cost in National Morale!