Then advertised at Craigslist, Zillow and FB Marketplace.

For example, 60's multifamily may have materials that 80's and newer does not so for that reason you prefer to stay above 80's product.

More from the rules in regards to advertising “All advertising, regardless of its nature and the medium in which it appears, which promotes either a licensee or the sale or lease of real property, shall conform to the requirements of this rule.

They advertise all over the Internet for 2 free workshops a day over a week period to see the "Guy".

However; once you're in that range the materials and finishes used are high end, and subs charge top dollar.

For example: Where can I learn about the most common problems (and home to spot them) concerning:FlooringThe RoofThe FoundationElectrical Plumbing/PipesPaintingDrivewayEtc..Can anyone point me to good info on this (repair costs, best materials, life expectancy?)

This site is full of great material. 

They advertise some pretty cheaply priced doors, so I'll make a trip out there this weekend.

Bank fees also matter, the #1 retail mortgage bank in the country advertises rates with about 2 points in junk fees ($10k in extra fees on a $500k loan on top of normal closing costs). 

Perhaps you pay for materials, but pay them for their labor afterwards, once you are satisfied with the work.But if you are hiring a GC for a $50k rehab, then you can expect to pay in several tranches, say 6 x $8k with $2k upon final punch list completion, or something along those lines.