Could it be that 150K houses dont exist on the MLS because the market is higher than that? The houses selling for 150K are likely foreclosures sold on the courthouse steps to all cash investors. If you had 150K (or whatever they are selling for on the steps) you could play the wholesale game too.
Worrying about flipper margins is a battle of futility. Focus on finding a good house at a fair price in the current market and everything else will fall into place. if you cant find that then wait until you can.
