The Illuna Market provides exchange of many useful goods. It is located in the Illuna castle and you can easily get there via teleport pad in the travelcenter.
There are a lot of smartshops where you can buy things for minecoins, but there are also shops, which allow you to get minecoins by selling gold or stacks of wood, stone or dirt. Additionally, there is a stall for special goods you need donor coins for as well as a small stall for beginners with noobcoins.
The different market stalls (with their color) are: