Need advice: Rent cash flow versus purchase price of Condo

[Ravi Sesh]

Hi I am looking to invest in a new build condo in Phoenix, AZ. The community has 4 different types of models 2B/2B, 2B+Den/2.5B, 3B/3B and 3B+Den/3.5B. How do I determine what is a profitable purchasing price based on what it will rent out for? I want to ensure that the investment i make has enough positive net cash flow per month of at least $400+ so that way I can own the condo in 15 years or less. Any advice on how to make sure the investment is going to be profitable and what rent will product + cash flow? Thanks!

Condo: average purchase price $300,000 for 3 bed with each private bath.