Hello, im kinda new to Unity and im on MMO. Lately i was thinking of an networking and i discovered that there is no network engine that is free or for a reasonable price. So basically you need to create your own? Or maybe there is some free openscource ? 
There are no free ones no, for good reason - its expensive and complex to build a networking engine, the closest thing you have to a free one is my SlimNet networking server: https://github.com/fholm/SlimNet You are allowed to download the code and use it to test, but not distribute it to anyone, so read the license carefully.
Thanks for reply fholm.
There is also Lidgren which can work nicely if your willing to code alot your self. The Nice thing about Lidgren is that your free to structure your server software however you want and have it optimized for your use.