But the props were in your name and they had a loan against it and then when it was done they bought it from you and you made a profit ??? 

We've done a lot of deals together over the years and I appreciate all the work he's put in over the years especially when we were doing really lean deals and there wasn't a whole lot of profit there for him relative to the work he was doing. 

Can get it rent stabilized, sell 4 profit, rinse and repeat.

The marketing isnt that important in my opinion but the professional photo/ video is a huge game changer and I dont believe that someone is going to make much profit at .5% on the listing side.

Save up some money, buy your first few properties organically and once there's experience and the start of a balance sheet go out and raise money from friends and family if you are still interested in the business. 

I guess we could maybe have the builder agree to the cost of the build and if we sell for more or less then the profits would go up and down based upon the selling price.

Profit split (20–50% if the deal does well).

If you have never done this as a full time business I will throw caution to the wind it is not as easy or as profitable as online forums make it out to be, and if you need money for living this probably is not going to sustain your lifestyle for the first several years. 

I did just this, and in 4 years sold it for a $200k profit and that’s how I bought my home and build an ADU conversion.

You being a “partner” and then paying the “profit” to the builder makes no sense.