The gold owned by the kingdom and the one owned by you adventurers are two different things. Appart from the small amount of gold they bring with thme, adventurers will most rely on what they find in the dungeons, and they will mostly used it to purchase things from the dungeons merchants. While kindom's gold is handled in much larger quantity, and is mostly used to unlock buildings and prepare adventurers.
How much gold is there in a dungeon ?
There are 10 gold piles in each dungeon. Each pile can have a 1-gold, 2-gold or 3-gold value. There is never fewer than 2 of each pile type, but otherwise the split seems random. So on the average is 20 gold (usually between 17 and 23).
Some subdungeons will have 5 random gold piles. These will again have the same values (1-gold to 3-gold), so on average finding such a sub nets you an additional 10 gold.
There is the "lots of gold" secret sub, that has 20 gold piles, giving you 40 extra gold.
Petrified monsters leave one gold coin when they are destroyed.
When there are multiple boss in a dungeon, the trophy they drop can be sold in the dungeon for 25 gold.
Black Market adds +1 gold to each pile, which - given the 10 piles - means you get an eventual +10 gold. Needless to say, if you find any of the subs with gold in them, it will be worth even more (or, if you are using IMAWAL and some means to break walls; the gold piles left are normally worth 1-gold, but Black Market also boosts that by +1).
The most obvious gold use is objects purchase from the shops. But keep in mind that objects can be converted, so gold is potential conversion points.
There are some other usage, depending on your situation :
- You can purchase piety for Tikki Tooki
- Some objects require gold to perform, such as the Crystal Ball
If you have some piety to spare in the end of the dungeon, you can spend it on Tikki Tooki boons: (+10 ) and (+10 ). Finally you can bring your money back to the kingdom. But while 50 gold is a lot of cash in a dungeon, it is really not much money in a kingdom...