how to estimate monthly rent income?

[Bryan Blancke]

I am new to investing. I have been looking for deals through the MLS and making a preliminary analysis using rentometer.com to estimate the average rent of units in that area. I do not have a rentometer pro account and I am only able to pull 10 comps a day. This has really been limiting my data crunching abilities. How do more experienced investors estimate the rent they expect to receive on MLS listed properties?