I would stay away from Craig's List, that's a good way to get scammed, robbed or killed. Buying from the classifies probably would be OK as long as they live in TV.
I look for cars using Autotrader, the last 4 cars I bought I found on that site. You can set your search for example, 100 mile radius, price $8000 to $12000, brand, model, mileage, etc.
Then I look at Yelp.com to see reviews for that dealer. Main thing is to find a dealer that doesn't add dealer fees. For example, a Hyundai from Jenkins has $899 added in dealer fees, from Hyundai of Central Florida in Clermont has zero dealer fees. There are other sites such as dealerrater.com, but I found reviews are more honest on Yelp.
My most recent car was a new Hyundai Kona and it was $3300 cheaper in Clermont than at Jenkins. Besides price, on Yelp Hyundai of Central Florida had great reviews as far as the dealer itself in customer service. On Autotrader click on advanced search and you can put in parameters of your search.
Autotrader Find Your Car
Yelp - Reviews
After you find the car at the right dealer, go to Kelly Bluebook and find what your trade is worth and what you should pay for the car you're buying.
Carmax in Orlando is a good company for used cars. I sold two cars in different years to Carmax in Baltimore and they paid me exactly the KBB wholesale price. Carmax has a large inventory and they are all over the country. They can bring a car from another Carmax if it fits your needs.
Kelley Blue Book | New and Used Car Price Values, Expert Car Reviews
Carmax
There is an Automax in Ocala, it's a different company and I don't know anything about them. Looking at their place, they have far fewer cars than Carmax dealer would have.