You want a used bike that is fairly new. The older they are the more questionable the maintenance schedule can be…also the more likely that the fuel lines, brake lines, etc are getting old and cracked and need replacing. That doesn’t mean you shouldn’t buy an older bike, but just realize there could be more work to be done to it to make it road worthy.
If you have never sat on a bike before, the sport type bikes will feel tight to you. You will want to find a standard bike to start on…they are the most neutral seating position…not hunched over the tank and putting pressure on your wrists, and not having your feet and hands out front…they can range from cruiser looking bikes to dual sport bikes to some that are nearly sport bikes…
The only problem is, there is a shortage of choices on newer standard bikes with reasonably sized engines…the GS500 and the Ninja 500 are two popular choices, and you should be able to find on in your area at a reasonable price…you could check out the Honda Nighthawk 250, the 750 would be more of a handful for a beginner due to weight and power…there are more choices in the dual sports, but they tend to have limited comfort in the seat.
You need to go to the dealers and sit on the bikes, that will determine which ones are going to “speak” to you.