Consult with an attorney to provide a purchase and sale agreement in your respective state with an assignment exhibit included. 

Reno Scenerio Off Market Purchase Price - $185k ARV = $315-335kReno - $55-65kHolding - $10kClosing both ends - $25k= $335 , $315-$285 =$30-50k gain  As-IS Scenario Purchase - $185kSale Price on MLS :$225- $235kClosing both ends - $20kHolding - $4k= $235 - $209 =$16-$26k gainIn both scenerios I’ll be 1031ing it into a new investment.

What's the purchase price? 

Even if you've taken a break and feel lost, the first step is to get to a meetup asap or just go to an Open House or view a property with your agent.

I want to purchase my sisters house as my first investment.

Gain is your net sales price minus your adjusted cost basis (purchase price plus capital improvements minus depreciation). 

The tax is based on selling price minus purchased price.

This will be my first home purchase, and I am aiming to invest in multi-family properties.What should I be aware of when purchasing a multi-family property?

Self-proclaimed Section 8 guru's online claim to do the latter and then find Property Managers after they purchase the property in whatever state, but I don't know how real that is. 

Purchase price: $645,000 Cash invested: $516,000 80% cash purchase.2,437 sq ft Duplex, with 3b 2b for the front unit (1331), 4b 2b for the back unit (1333).