What market are you in?

(I'm not really interested in the Orlando/Disney market.)

Any advice on most efficient and costly ways to obtain marketing lists in S.

As an investor, your primary goal is probably to buy at the lowest price (you make your money when you buy at below market value), fix it up, and either hold or sell/flip.The seller might realize they "don't know what they don't know"....in general, investors sometimes come across as "transactional" (they ran the numbers, and just want a yes or no from the seller). 

I'm thinking about ramping up my marketing and having agents send me deals with their criteria.

If there is any way you can avoid marketing to section 8 you will be far better off especially in regards to the quality of tenant you will get. 

@Dave Rav - I agree with the others that there is no really good way to estimate insurance costs, but I've found some consistency within a particular market/zip code if the rebuild costs and deductibles are the same.

I have searched online and found no company or market for this type of transaction.

That is a very general question and each area has its own market conditions so what works well in one area may not in another.

Sat on market for 4 months before they dropped to $125k.