Well - you can UPGRADE all your upgradable items - you get some gold from the battles
also as said before - sell all you don't really need
But than - hmm - maybe you could try that Sacrifice spell - buy low cost armies and sacrify them to increas you high cost armies in numbers (change peasants into dragons like way)
after this I would be out of hints myself (I know that I spent all my quadrilions in the castle of dwarven prince for mana crystals and some runes... ) but I never experienced lack of money at the end of the game (true is that on higer difficulty levelst I was saving money everywhere, maxed the TRADER skill ASAP and sold everything I didn't need, even backup armies like spider or snake eggs, thorn sprouts... I sold all scrolls I didn't want to use in my spellbook (I have to save my mana crystals as well) and I bought only armies that are cost friendly (like vamps and ghosties) at the beginning of the game (in the swamp cementry you can buy normal ghosts, if you are lucky even vamps, if you are extremly lucky the LVL 4 vamps) also if you complete the furious paladin quest and he is changed in undead - you can buy cheap undead armies from him. (When battles as fought correctly, I could always get + 5% ~ 15% of gosts more after the combat) So when my LEADERSHIP increased - I used the ghosts that I stored in the back up slot, instead of buying new ones)
But when I would already be in a situation when I am low on money and armies and all isles of Endoria are cleared out - I would be screwed as well
