You can identify the two highest retail price ranges, in greatest demand, per zip code where you can list the rehabbed property.You can use the Realtor to help you find deals and also use Wholesalers.

-Tenant started demanding more pest inspections minutes after I start to enforce rent payment.

Representing both buyers and sellers. 

Since there are no realtors involved, how can I be secure that when I put money down that I am getting something, or that the properties don't have other liens or that this seller even really is the owner???

Nor does the level of demand for MBS or credit default swaps.Additionally, mortgage debt owed by U.S. household was > $12 Billion before the housing crisis in 07/08.

I have to agree with @Alex Craig that the seller knew the troubles with this home before you closed on it.  

Hello all, I have a quick question, I am new to real estate investing and recently came upon a property where the seller is asking for 23k.

but a lot goes into analyzing a deal, including: $/SF, Average Days on Market in the area, how easy or difficult it is to get permits in the area, how long the flip would take, comps/ARV, Rehab, Rental Rates, how the area is trending, holding/carrying/hard money costs, closing/commission costs etc.If you can analyze the deal, you can then negotiate the deal with sellers, buyers, and lenders.

In the mid 1980s he started in the manufactured housing industry as a seller of homes.

So given that statement you have two options; 1) Offer the price you feel is justified and see if the seller accepts, 2) Determine this deal isn't for you and work on finding the next one.