I appreciate it, @Garrett F Anderson!
The mortgage cost can be used by a simple calculator found on Google or a lot of other websites.
Tax rates can be found on your state's website most likely. I found mine on the MI Dept. of Treasury website. be sure to use non-homestead taxes as this is a rental property!
Instead of budgeting a number, I used percentages for my expenses, management, capex, and vacancy. This will all be based off of what you are receiving for rent. These percentages will be determined by a number of factors. Do a little bit of research to find out what percentages make sense for your situation.
Plug all of these numbers into a spreadsheet, BP calculator, etc. and find out what your cashflow will be. My current Net Cashflow is $224.55. This can go up or down in the future based on the changes in the various factors that go into determining cashflow. That's why it's important to find a number that you think will be enough cushion to protect you from the fluctuations.