If you're investing in real estate you always want a mortgage and you always want it cash-flow positive. If it's not cash-flow positive on the first day of renting it out, then you don't buy the property. Investing for equity is about the dumbest mistake some real estate investors make. Always invest on cash-flow. Investing for capital appreciation is a recipe for disaster. With positive cash-flow, the underlying value is irrelevant.

When I say you "always want a mortgage" I mean that if you have a mortgage you have your tenants paying for the house. Your cash on cash return is far higher. If your potential property doesn't support that, then find another property. Paying $200k cash for a house that nets $500 per month is far less interesting than buying 10 houses at $20k down that each net $200 per month -- and it takes exactly the same cash.