Cost to build is $350K (I am managing it all myself and calling in favors around the city to get low rates on materials and labor).

Plus the hours of material participation. 

However, he asked me to sign a one-year Exclusive Right to Represent agreement, as presented to him by his brokerage.His interpretation is that it applies only when he materially assists me, but I think the boilerplate brokerage language he was given reads much more broadly:"If during the term of this Agreement Buyer enters into a contract for the purchase of Property through the services or efforts of the Broker or Buyer’s Brokerage Firm, or by or through any other persons during the term of this Agreement" (emphasis mine).My concern is that, under my interpretation, if a fellow real estate investor wants to unload a property or if I get pointed to an opportunity by a former agent, colleague, or friend, this agreement could create an obstacle to moving forward with the deal.In the end, I didn’t sign.

If you research recent sales you can always provide the appraiser a list of those sales.One of the best ways to insure a higher value is to update the property using materials and fixtures that are popular and common in the area.

Let's assume that the neighborhood is a C class and the median income of the city is greater than 3X of the market rent.Here are some of the considerations I've come up with so far:- Units are in need of renovation and capex is too high or not available- Unit quality is not the same as market - Seller is worried about losing tenants due to increase- Vacancy rates are high or filling units have been difficult- Rent increase would take multiple increases over multiple lease periods to get to market rate if seller is trying to retain the same tenant- Seller inherited property and just want to liquidate- Seller needs to liquidate quickly (financial burden, sickness, quick exit from land-lording)It seems like I might be missing a warning sign about a deal if they are selling with current rents that are under market; but again, this seems to be most of the properties I've underwritten.And in the same vein, what should I be worried about when purchasing a deal with under market rent with the intention of raising them after purchase. 

And does the person doing the labor get paid or only the materials paid for by the partnership?

Rehab costs and ARV (After Repair Value) are key parts of evaluating deals, so it’s great that you’re diving into these concepts early.For rehab costs, creating a rough estimate starts with understanding the scope of work and local pricing for materials and labor. 

We had to repaint the entire unit because the material he used left oil stains everywhere.

My wife and I were in analysis paralysis for sure, but then the academy dropped and we were sure we wanted to get into RE, but didn’t know how and this course was WAY cheaper than comps that ultimately just try and sell you a conference that just tries to sell you… on and on plus like you said, we got most of our money back and got to keep the material. 

The latter would create mortgage rates issues, the former will eliminate a lot of fake demand and some material real demand in the housing market that is bid side.Mortgage rates higher + build costs higher(less labor + tariffs)= Kill demand.