For starting out, I would suggest working on commission sales. This saves you from having to buy the car. You have them sign a contract that gives you permission to sell the car, and that you will get say 10% of the final price. You then mark up the car 30% or so from their absolute bottom dollar. This gives you a range to work with so you can lower your price to the buyer. They are thinking they're getting a better deal. And of course the higher you sell the vehicle, the more money you make. How to find people to list on commission? Any vehicle sitting on the side of the road, talk to them. Put up a sign or banner saying that you put vehicles on your lot on commission.
For any vehicles you bring in, make sure to fully detail them. It make seem like an annoyance, but it will bring up the value of the vehicle for sure. I worked at two different car dealerships and my family owned an RV dealership for 10 years. A good waxing, full vacuum and even shampoo, tire shine, polished rims, clean windows and dash, and a clean smell really helps. We once bought a mini van for $250. The van was TRASHED inside. The family had many small kids so the seats and carpet had candy and drink spills all over. You couldnt sit in it without gagging from the mold. It took one full afternoon of hard scrubbing to clean that interior, with some hard chemicals. Two weeks later we sold the van for $1200. All it needed was a good cleaning.
There is money in it, but you have to make sure you buy the right vehicles. Research your market. You want to move vehicles, not sit on them. If you can afford to sit on vehicles later on, and have a good location, you can make some money with that too. There is one local dealership that is WAY over priced. But they manage to move vehicles. They sell less in a month, but its priced high enough that they still profit more than any of the other local dealerships do.
If it works out for you, look into small investments on vehicles that will up the price. Can you upgrade the speakers for $50? Can you upgrade the stock AM/FM with a cd player? Look for OEM parts that will be compatible. Can you upgrade the stock steel rims to aluminum rims? Can you find a set of used stock rims from another vehicle that will fit? Look at local junk yards and craigslist for good deals. You need to make your vehicles better than anyone elses. I also highly highly suggest downloading the Factory Service Manuals for any vehicles you are working on. You can download them for free if you know what you are doing. DO NOT waste your money on the Haynes or Chiltons manuals. (If you need 70s-90s Nissan FSMs, let me know. Always willing to help out a NICO)
One point of interest, depending on how much you can sit on products and how mechanically inclined you are, is to part out vehicles. I parted out a 92 Camry this summer. I had $150 in the car, sold the motor alone for $500. Car scrapped out at $200. Tires and wheels sold for another $100. I still have the tranny for scrap, all the lighting, and the seats. With price for gas for hauling, i still profited $650 and have parts left over. If you buy your vehicles right and have time to sit on it, you can make a lot of money parting them out. Check local scrap prices, laws of the state/county, and rules at the local yard before hauling anything in.
There is money to be made in automotive, but its not as easy as it used to be. There is a lot of money to be made from scrapping too, but it is hard work. Dont expect to get rich from it, but the scrapping can be a nice chunk of spare change if you save up all your copper, aluminum, batteries, and cats. I do the scrapping for my exercise, cause the gym aint my style. If anyone is interested in scrap ideas, hit me up. Would love to discuss more on it or foreign vehicles.