I was in your boat when I decided to buy new from dealer. Last mower I purchased was a used JD X300 via craigslist for a decent price. Didn't realize mower deck was bent near one of the spindles causing an uneven cut until after I drove back home with it. Beat it with a BFH and was still nearly 1/4" difference when blades met in the middle.
Same story as someone else mentioned, they claimed to be moving, no longer needed a bigger mower, and needed cash for down payment on new house. Realized after that they damn sure knew about it based on how willing/quick they were to accept a lower offer when I met with them to look at it.
If you're trying to save cash, you may call around and see what each dealer has in their inventory. Most will cut a deal on last year's mower model to get rid of it. I think only difference between my 2018 and a 2019 was a black piece of steel added to the front of the platform where your boots rest.
I think Scag has a dealer locater on their website. There are quite a few small engine shops that are also dealers if you want to call around and see about last years model. I think it's still early enough in season there may be a few left out there.