We do apologize for the extreme delay in answering this topic.
For adding different income sources, please make sure to give different budget name or category for each budget item. Creating two identical budget category is not possible as the system will overwrite the previous existing budget. Mint will prompt you with a message box when doing so.
I would suggest creating custom budget categories. See the images below for guide.
1. When creating a budget, select the main category then select the option to Add/Edit Categories
2. The next page gives you the option to Add a new category
3. Type in your own category, then Save it. Click Okay to go back to Set a Budget page.
Additional Notes:
Currently there seems to be a bug in the Set Income Budget page. Every month is defaulted and cannot be unselected. We are already looking into fixing this issue.
There is also an idea topic opened, requesting Variable Income Budgeting. Our product team is keeping an eye on Idea topics such as that one and is continually taking users' ideas into consideration.
Have a great day!
EMPLOYEE