MyPlaza Turbo is a fun plugin for MyBB, adding a shop/money system to the boards. Note that you have to be a registered member to be able to use this system. How money is earnt, and what can be done with it, is strictly defined by your administrator. A common method is earning money through activity, such as posting - if your administrator has enabled this, see the Income help document for more information.
The money system on this board is named {1}

Purchasing Items
Once you earn enough money, you may want to actually put it to some use. This is where item purchasing comes in. Again, what items are available are defined by your administrator. You can see what items are available by clicking the "MyPlaza Turbo" link near the top of the page (next to Open Buddy List). Once you have entered the plaza, you should see a list of items (assuming your administrator has added some) on the left. Simply click what item you want, from the list, then confirm your purchase by clicking the "Buy Item" button on the right.