Coins are an important part of Empires & Emperors, just as money is an important part of real life. However, coins don't just grow on trees. Making coins is an important process, especially if you want to run a civilization, city-state or a town. There are many different ways to make money, some of which are detailed here. Not all of these methods are usable to gain personal money, however, some add the money directly to the town treasury.
One of the easiest ways to gain your coins is mining. You can use the Bank at spawn, at another Civ or build one yourself to sell Iron, Gold, Diamonds, and Emeralds. You can also sell the gravel and dirt you find at the Global Market too. With your cobblestone, you can use a Trommel which you can build in your Town. This will sift through the stones and returns precious minerals like emerald, diamonds, gold and iron.
If you are in a civilization has researched the tech to build a Cottage, you can build a Farm plot to grow crops to put into a Granary. They feed with Bread at first and after a certain upgrade, they will require Carrots, Potatoes and Beetroot, even raw porkchop at the end. The Granary takes the food out automatically & feeds it to a Cottage. That Cottage then produces money, which goes into the town's treasury. There are 9 main levels of a Cottage, and the Bonus Level 10 which is only available if you have the Oxford University wonder.
Your Happiness level and your Government change the amount of money you will produce. To help boost your money output, you can research technologies that increases the cottage income and technologies that allow you to upgrade your town level, which results into the build of more cottages. Be careful ! Remember you need to farm a lot to keep your cottages from starving.
If you're in a civilization has researched the tech to build a Trade Outpost, you can build it on bedrock pillars that represent a Trade Good. Then, it will give you the Trade Good. Only the Town's founder, mayor, assistant or Civilization's founder or leader, if they have the permissions on the plot, can retrieve the goodies. You then put them into your town hall in item frames' trader. Every hour the town will automatically collect money from the trades and will put the money into the town's treasury. Be carefull though since they will respawn every week at the same time! This means you will have to walk back to the Trade Outpost and get the trade good again.
You can check out the Global Market at spawn, which has a variety of items you can buy and sell. The prices in the market go up and down based on the people who use it server-wide who buy/sell items in it. If the price is green, the price has been rising. If it is in red, then it's been falling. If the price is white, then the price is the same. It is usually only black if the server just started or if its database was reset.
There are different tiers of Custom Mobs. There are Tier 1 to Tier 4. The Mob types are listed there. When you first start out, you can only attack Tier 1 Mobs. But as you get tech for better armor and weapons, you can attack the higher tiered mobs. In order to start killing those Custom Mobs, you require to build a Dungeon Portal.