I've looked around on this forum and have yet to find any information on how to mod the cost of leaders. I'm sure it is possible to do as all I want is to mod the cost of veteran leaders to zero in the hopes of giving myself an experience that is closer to Disciples 2 when all I had was "my character" as opposed to having to put up with the "hero's" in Disciples 3. Can anybody help me out here? Also, if there are any mods to include the exporting and importing feature that was in Disciples 2, I would be greatly appreciative as well.

There isn't a real good answer to adjusting the cost of veteran leaders.
There is a cost that can be modded for rookie leaders. this is located in there stat file.

Using the Forest Liege for example, you would open Disciples III\Resources\Profiles\stats\elves_leader-forestliege_stats.char using notepad.

Scroll down or search for the cost entry which is 500 by default.

Looks like this: cost 500;

Just change the 500 to something lower. I have not seen a way to adjust veteran leader cost yet and I have done a lot of modding. I'm not positive if the cost of a veteran is a straight multiplier of the cost of a base leader. Often veterans cost about 2000 in Hard difficulty. If it was a straight multiplier, making the cost of a rookie leader 200 would make the veteran cost 800 in this example. Only I don't think it works like that. I haven't verified this, but It might be that the veteran leader cost is independent of the base leader cost in the stat file.

For one thing. The armor and amulets, rings etc.. that a veteran leader is wearing increases the veteran cost as well. So lowering the cost of armor would lower the veteran cost to some extent. But that screws up balance elsewhere.

Like I said, no good answer, but I thought I'd say what I know.

The import/export leader isn't available anywhere as its probably not coded anywhere in D3.

There is a way to make veteran leaders affordable, but its not as simply as lowering cost. One way is to stay in the previous act long enough to buy armor, rings and amulets. Armor and amulets, etc are brought to the next act with the main hero, unlike potions which are lost. They only sell for half price of course. But if you bring 6000 worth you get 3000 when you sell at the start of the next act. Enough for 1 veteran anyway.

One thing I mod in my game, is I find a building that isn't used for any function near the start of act 2. Then I mod that building to give 2000 gold. It could give any amount really. The problem with that solution is that building type may appear in other acts in different locations. It can't be isolated to just one act unless the maps is custom. Modding a building like this has a few more steps than adjusting a start up leader cost.

These are some work arounds to get gold for veterans. Not a perfect solution, but works in a pinch.

Thanks for the Help Redgreen. Do you think that there maybe a way to supplement the Hero with one of the leaders? For example is there a way to replace Lambert from the Empire with an Archmage in terms of character model and skills?

Yea another leader can be swapped in for the main hero such as Lambert. But only at the start of a campaign and it gives things a fresh look. Only the stats have to be balanced just as Lambert is. Leaders generally start a bit nerfed attack wise cause there armor upgrades buffs them up.

I've swapped out the main hero by switching the contents of the 2 leaders profile files. The real bugger is all the armor set items have to be modded so the new main leader can equip them. Actually for an archangle leader. You would need to make a second copy of all 3 of Lamberts armor sets. Rename thme for the Arch angel for both the armor items and armor icons. Often the armor stats need to be adjusted also to fit the specialties of a different main hero. Of course a new leader won't change appearance when switching armor like Lambert did. Because the main heros are actually made of about 6 model groups which each piece of armor being a seperate model.

It isn't hard to do, but a lot of putzing. Then your still left with the veteran cost problem.

Its hard to keep a second unit strong enough. Almost always the start of a new act is very tough, making it a matter of survival to use your main hero with more leadership, stats and skills. I generally bring along a 2nd and 3rd veteran to protect guardians against weaker stacks, then once my units have leveled enough and the AI is weakened, I transfer the leveled units to a veteran. Then he has enough support so the vet leader can reach his max level in the act. Getting one maxed vet isn't too bad, getting 2 maxed vets means staying in the act forever. Unless it has a trainer. All maps should really have a trainer right at the end in the campaign acts IMHO

Thought of an easy mod to allow more wealth to be brought to the next campaign. Artifacts stay with the leader as he moves to a new act. But if one buys armor/artifacts to sell in the next act, they only sell for half value.
It would be simple to mod a token that sells for the same amount it costs. So at the end of act1, a player uses his remaining gold to buy tokens to sell back at start of act 2.

EDIT- disregard this entry, I got mixed up, thought the sell price could be changed. I think resell is always 1/2 original cost. Foiled again!

Actually there might still be a way using spells. A bunch of us modders worked out mana conversion spells. Along those lines, I think there was a way to use mana or stones to cast to get a rune. It may even be possible then to trade stones for an artifact, which is what the token would be. If the artifact id worth 2000, it would sell for 1000. Just bring to next act.
Even a rune would do, as runes also are brought to the next act in campaigns.

THis would be a great way to have a use for all unused stone in game, and would greatly solve the not enough gold to buy veteran leader problem. Its on my to do list.