Hi Ted,
Determining property value is part science part art: you'll need information of similar property sale price (in the same location, vintage, type, etc). Look at their cap rates to understand what cap rate this property should sell for. You also need to calculate the NOI (net operating income = income - expenses). The ratio between the NOI and the price should give you the cap rate. That's in a nut shell, and I encourage you to learn more about it before making any purchases.
As for rent - engage a reputable property management company that can advise you on rents and expenses. Look at market reports (we use CoStar) to see what other nearby properties charge, and if you don't have access to these reports, make phone calls and/or shop these properties and see what they offer (amenities, how nice the apartments are, what's included in the rent, their other fees, move-in specials, etc) to determine if and by how much you can increase rents.
Again, I encourage you to learn more before making you first purchase. Read books, listen to podcasts, and dive deeper before becoming a real estate investor.
Ellie