How Do You Value a Commercial Deal?

[Melvin Holmes III]

I have a Commercial Deal where the asking price is $300,000 there is 3 tenants in the building. A Grocery Store,Day Care, and Church the owner just wants to sell the whole building which includes all three units. As an Investor how do you run the numbers for a deal like this? NOI? ROI? The neighborhood is below value basically in the hood.