Right now, year or two old used cars are selling for more than they are worth - so if you are looking in that price range, a new car may be a better deal.
If looking for used, I've bought all the ones I didn't regret off private party sales from Facebook or Craigslist. Just lurk daily for about a month and get a feel for what the ones that sell are priced at, and know that the ones that don't sell are probably priced a little high. When you spot a good vehicle at a good price, move! Try to get in to see within 24 hours. If it's at a good price, it will sell quickly. If you want to buy it, get it taken to a dealership for an pre-purchase inspection (Usually $100-$200). If you had a mechanic you trust, he might do it for free. If it's good enough buy it.
If looking for new, then the first step is to find the online forum where the power owners of that make and model hang out, and find the forum thread or spreadsheet where they post how much they paid. This is incredibly powerful, and is the key to your success. It will often surprise you how low dealers can eventually go. Pick a price low from the list, but not the absolute bottom as your plan.
Next step is to contact by email many dealers around, tell the vehicle you are asking for, say you are shopping around, and request an out the door price. If you shop say eight dealers, you will be amazed at how much these prices may vary (like 10% of the value of the vehicle). If you see what you are looking for, go for it, and walk out if they change the price later.
* Lease mileage seems to be trending downward. * Overall reliability is trending upwards (easy to get 200k+ miles) * This places a lot of 1 to 2 year old vehicles in the "almost new category"
Combine this with certified pre-owned program, you can pretty much get a "new" car for 30% less. This is inflating the price of cars with low miles since they seen as nearly the same as new cars.
Paying 2-3% more and saving a lot of hassle seems much more reasonable.
They take a small commission (usually from the dealer), then contact a bunch of nationwide dealers on your behalf. The prices they get are better than or very close to the best you could personally haggle, and it takes like 2 minutes to make the request.
If new - the best bet is to call your local dealers and talk to them. I'm aware of many dealers that haven't turned a unit in 3 weeks now, they need the business and likely will be willing to give you a great deal because they need a move inventory.
If used - I would wait until some of the auction houses re-open and try bidding on a car. If that's a little stressful (it can be) then I'd look at Carvana, Vroom and Shift (depending on your geographic region).
From there I'd look at local used car dealers - don't let them game you or try - Carvana/Vroom/Shift all recondition to a Lexus CPO (Certified Pre Owned) standard you just can't legally say that if you don't have the approval from the manufacturer (another weird quirk) - you should be able to find a like for like vehicle between Carvana/Vroom/Shift & a local dealer.
Whoever gives you the best deal take it, but both online and in-person dealers are marking down inventory.
If you can wait a few months, the prices will be lower with all those vehicles come off-lease.
Keep in mind that with Hertz filing for bankruptcy that other rental car companies aren't that far behind, so there could also be a massive influx from those folks needing to liquidate some assets.
If you don't know what you want, or don't know anything about the make and model you're buying, you will be taken advantage of.
It's perfectly fine to walk in to a dealership and look around, touch and squeeze and sit in all their cars to figure out what you like. Take one for a test drive, or five. Don't commit to anything.
Before buying a car, you should ideally have picked out a specific car from a dealer's lot, with the specific make, model, trim, and options you want. Price that specific car on kbb.com or trucar.com so you know the average price range for it. This is the only way of knowing if a specific car's price is "good" or not, because you cannot trust the dealer on this.
I know three people who have bought a car through that program and they have nothing but praise for the experience.
The whole process was pretty pleasant, people were pleasant, the car was great, and now I still come over to get it serviced.
In retrospect they were a little too eager to accept my offer which was way below sticker, so I was probably off on their factory price, but I figure I'm fortunate that I can afford to not obsess about a +/- $1k and do better things with my life :)