I've gotten 3 quotes for an approx 400 sq foot master suite addition (plans already approved by the city) and the least expensive was $150,000 - tile, fixtures, etc not included.  

I wrote a blog post last night that may help prompt some additional questions for you to use in your search.https://www.biggerpockets.com/blogs/8756/51616-tru...

Occasionally, you will find private money lenders that require a percentage of profit on the sale, rather than, or in addition to, the other fees and/or interest.Loan terms can also vary, but most private money loans tend to be about 6 months.

For me it makes sense to contribute to my 401k, realize the tax savings and simplify my life (by not managing additional assets in real estate).  

So what kind of terms would I want to offer them (the purchase price would be around $105k) and what would I be looking at getting after the sale (how much of a discount will I sell it at)?

Also good tip on buying over 1500 at home depot, I was not aware they discount past that threshold. 

The first flips were during a super hot market, so 1 was an easy rehab and the other I purchased at a discount for cash simply resold 45 days later for profit.

Hi, I am looking at doing a rehab and addition on an older home. 

Hi, I am looking at doing a rehab and addition on an older home.

I would make sure your insurance quote includes additional fire coverage.