There are differences between buying a product from a retail store, and people who "flip" cars, houses, or anything else.
Retail outlets are there because of the system of distribution in small quantities. You can skip the retail store if you are willing to purchase in bulk. Also, when buying retail, you have an expectation of quality. If the product is spoiled, damaged, or otherwise unacceptable through no fault of your own, it can be returned for refund or exchange.
Flippers buy low and sell high. That is their business. In the housing market, it might be necessary for them to invest in some upgrades to realize a profit, but usually, there is some compromise made in the quality of the product or workmanship, to maximize profits. If you find and issue after the purchase you are most likely going to have to live with it, repair or change it yourself, or get a lawyer. You simply can return it for refund or replacement as you could when purchasing Groceries, appliances,and other goods.
The same holds true when purchasing cars from a flipper. In many cases the workmanship is not of the best quality, parts are used or substandard (read cheap), and warranties are none existent.
Remember, the goal if the flipper is to make as much money as possible, while spending as little as possible.
I went to look at a 72 Swinger with a friend. Upon approaching the car it looked Wonderful. New roof, and paint decent upholstery, 318/2bbl. Advertised as having a 727 and a 8 3/4 Sure grip.
It was a 904 with a 7 1/4. A pass along the quarters with a magnet found places where the magnet would not even stick to the body. The new vinyl roof also caught my attention, when we pulled the car out into the sun light. I saw bubbles on the "C" pillars, and while running my thumb along the roof above the windshield trim I felt a number of sort spots. Obviously this car was painted and had a new vinyl roof applied over some body rot that was neither repaired nor neutralized.
Further inspections found such things as the glove compartment box being made of and old Cheerios box and painted, poorly fit headliner, different keys for the two front doors, and on and on. The seller was Asking $7500 for it. When I asked to see the paperwork for the car, I found that he never registered the car, AND it had a "salvage title". My buddy said he wouldn't have noticed any of those things, and thought the car look really good. He was right, it did look really good, until you look a little more closely. It was not as advertised, and that's VERY typical of "flipper" cars.
In this case it was a real rip off, to boot.
I asked if I could take an oil sample from the car. The seller declined.
I asked if he could show me the paperwork for the paint and body work. The Seller declined.
I asked if he minded if I copy the vin number and fender tags so that I could do some research on the car, He declined that, too, and asked us to leave.
Obviously this guy was not looking to sell the car to a MoPar enthusiast, but, when you advertise a 40 year old car for sale you have to expect that the people who respond to such an advertisement are knowledgeable. Also obviously, he did not expect that. Had my buddy gone there without me, or anyone who knows these cars, he might have spent $7500 for a POS.
Before we left I offered the seller $1500 for the car as is/where is. He declined. I'm sure some poor sap dropped over $7K for that car and purchased pure crap, and had no recourse after the sale.
That's the difference between buying from a flipper and buying "groceries".