I am not more concerned with the profit (low ROI here) but more concerned with if I accounted for everything, or did I underestimate something?

Hello, I am interested in buying a small single family house in a decent neighborhood (average median house price around 450k), but the seller would want to sell the land (50x100) next to it together for an extra 100k to make a deal. hypothetically I can negotiate it a lower price for the land (any suggestion on how to determine the value for the land), what kind of investment can I make to turn the land into something profitable rather than just being wasted?

I'd guess she'd just take my payments and make her mortgage payments each month and maybe keep a little off the top as profit.

It really kicked in how much of a waste I'm making on living in rentals when I started talking to friends who have purchased, and realized their mortgage is cheaper than my rent, and they turn a profit when they sell.... 

Is this like when will arnet tried to take over for Michael scott in The Office"I have a 3 step plan to double profits here""ok great, whats the plan?""

The neighborhood already started gentrification  offering solid cash flow projections.The deal offers both solid income and a strategy for a profit at exit. 

That way we would have the time to get someone else in on a lease option after we bought something else to live in, and have a margin in the rent to make a monthly cashflow. 

He currently has not offered to make any concessions to his profit line except that he's doing the line items that are over "at cost" and is attempting to justify this by the fact that the home will still have significant equity even with the overages.We are still moving forward, framing is set to begin next week.

They supposedly are a non-profit org that helps provide housing for homeless which works similar to Section 8.http://www.abodeservices.org/Curious if anyone has worked with them and can share your experience?

If it's a marginal deal and you have little to no experience you should probably just fix your credit.The money also has to come from their funds sourced from their asset statements over the last 60 days in order to get approved by the lender.