How to calculate Rate of Return for an investment property

New to the investment world. If I pay all cash for an investment property, how do I calculate annual rate of return, is it:
(total rent - HOA fees - Property Tax - Homeowner Insurance)/Purchase Price? What percentage would be a good deal?

If it is cash offer and the ratio of (monthly rent/purchase price) is around 120, is it a good deal? What is a reasonable ratio to be considered a good deal since it is cash offer?

Thanks in advance for all your inputs.