The SonarQube Community Edition is for free. It can handle only 1 branch per project.

And these are the editions which are not for free:

• Developer (https://www.sonarqube.org/developer-edition/ )
• Enterprise
• Data center{}

(See https://www.sonarqube.org/downloads/  to compare all 4 versions.)

Simply said - the number of lines of code determines which version can/must be taken.
The number of lines of code also determines the price for the license.

See https://sonarsource.com/plans-and-pricing/ 

The editions which which must be paid have these 2 advantages (over CE):

• PR decoration
• More than one branch

While we expect that the Developer Edition is expensive - we should at least know how expensive.

Unfortunately there is no overview comparing all the different versions with all its features (at least I haven't found).