Hi 
It is indeed possible to monetise your Discourse forum through plugins such as the ones listed below
I’m glad that you want to have an online community 
However, its not as easy as just creating one, you need to know the costs of running your community etc. Especially if you are asking others to pay for it, you need to make sure that your community adds value to members so they stick around. An easy way to do this is to show the purpose of the community to users so they understand why they are there.
There are also a lot of resources available here to help you grow your community such as the Community category and the Discourse Blog. Feel free to ask for help 