Inevitably, the PCs are going to pick the wealthy nobleman's pocket, uncover the villain's stash of cash, or loot the dragon's hoard. In other systems, players keep track of individual coins and the things they buy have a specific cost. In DLA, wealth and treasure are handled with aspects.
Having a source of great wealth as a character is rare and gives you an advantage over other characters. Therefore, it's treated the same as any other special power or ability. If you want wealth to be an important part of your character, then you'll need to make a character aspect that indicates this. Anytime you want to spend a significant amount of money, make a roll using an appropriate approach. You may spend a fate point to boost the result by invoking the aspect. Depending on the cost of the item, the GM may rule that your wealth is not sufficient or that purchasing the item will deplete your resources for the rest of the session.
As always, you can attempt to create an advantage in order to raise the cash needed for an item. If the Wealthy Solamnic Noblewoman needs to raise an army to aid in the defense against Ankhar's forces, she may need to raise taxes on her subjects to perform the task. Of course, she'll need to convince the people that it's worth the sacrifice, so giving a spirited speech that appeals to their sense of patriotism may be called for.
Occasionally, it will happen that the PCs have killed the dragon and looted its hoard of treasure. Now they have this liquid asset that they will want to use at some point. When this occurs, the treasure should be represented with an aspect similar to a scene aspect, except this aspect has it's own stress track and it follows the PCs from scene to scene until all of the stress boxes are checked off and the aspect expires. The number of stress boxes is determined by the GM and should be representative of the value of the windfall. Any invocation of the treasure aspect expends at least one stress box, and confers the same benefits as spending a fate point on wealth related actions.
The most important thing for both the GM and players to remember is that wealth, in whatever form it takes, should be used to push the story forward.