I am trying to support them by finding investors to assist in buying lots and financing  their construction.I am familiar with the actual development side, but not so much with the investing and deal making (that's why I'm here to learn more), when I connect a builder with an investor, what would be a fair price to charge so I am compensated for my effort.

Note that you may have more tenant-to-tenant issues to deal with though.As with any real estate investment, you pays your money, you takes your chances :)

How did you find this deal and how did you negotiate it?

I have been looking at deal machine and propstream.

It's definitely not a final deal yet, but I wanted to see if anyone has general gauge of the rents in the area.

This extra payment deal is for consumer/homeowner that will spend all the money he has available on cigarettes, beer, etc. so he “fools” himself into “painlessly” saving money by building extra equity in his one big “investment”.A professional investor should NOT need to “fool” themselves into “forced” savings.  

I found this deal through my PM.

I still think I got a really good deal on the work.

Here’s a detailed breakdown of these two types of markets and the factors that contribute to each:Cash Flow Market, a cash flow market is one where rental income exceeds the expenses of owning the property (mortgage, taxes, insurance, maintenance, and property management), resulting in positive monthly cash flow for the investor.Key Characteristics:High Rental Yields: Properties typically have high rental yields compared to their purchase prices.Stable or Slow Appreciation: Property values increase slowly over time, if at all.Lower Property Prices: Generally, property prices are lower, making it easier to achieve positive cash flow.Higher Rental Demand: Strong demand for rentals due to economic factors, demographics, or local employment conditions.Factors Contributing to Cash Flow Markets:Economic Stability: Stable job markets and steady local economies that support rental demand.Rental Market: High percentage of renters compared to homeowners.Affordability: Affordable property prices relative to rental income.Local Policies: Landlord-friendly laws and regulations.Appreciation Market, an appreciation market is one where property values increase significantly over time, offering substantial capital gains upon sale, but rental yields may be lower, resulting in lower monthly cash flow.Key Characteristics:High Property Value Growth: Significant annual increases in property values.Lower Rental Yields: Rental income may not cover the monthly expenses, leading to lower or even negative cash flow.Higher Property Prices: Generally higher property prices, which can make it harder to achieve positive cash flow.Strong Economic Growth: Rapid economic growth, population influx, and development.Factors Contributing to Appreciation Markets:Economic Boom: Strong local economy with job growth and high-paying industries.Population Growth: Influx of people moving to the area, increasing demand for housing.Infrastructure Development: Significant investments in infrastructure, amenities, and services.Desirability: High quality of life, good schools, and attractive neighborhoods.I hope this information finds you well. 

Begin by assessing the area's overall appeal, including factors like crime rates, school quality, and amenities.