First turntable advice

Pro-ject Carbon Debut at $399 is the usual suspect, decent arm with decent cartridge included.

Agree with Schubert. Pro-ject Carbon Debut is a "plug and play" TT that comes with a good tonearm and an Ortofon cartridge. It comes to you already set up.
http://www.needledoctor.com/Brand-Stores/Pro-Ject-Debut-Carbon-Turntable

I added a turntable to my system after about 20 years of not having one. I had first picked up a used Denon direct drive off of eBay, which lasted about a year before the motor died. I purchased a Pro-ject Debut Carbon turntable, Musical Fidelity V-LPS phono stage, and the acrylic platter upgrade. All in, the cost was about $650 all new. It is a nice piece of gear, the included cartridge sounds good, the purchase was a smart one. The only thing I miss from my turntables growing up are the auto start and auto return features. Other than that, it will serve you well.

Rich

Stay with your preference to buy used. Turntable rigs are popular so there is a wider audience for upgradeitis. You didn't state your budget but, whatever it is, you will get more for your money used, here on Audiogon. If practical, buy locally so that you can audition the setup. Check the synergy between table, arm and cartridge. Again, this is most apparent during audition. Also, if you buy locally you can carry it home yourself versus trusting common carriers. Don't be surprised if your focus changes from digital to analog.

Don't buy used, you already said you know nothing about turntables, buy a new one with cartridge already installed.

A new $299 TT with cart correctly installed will sound better than the best one in the world without the cartridge correctly installed, and the chance in buying a used table set-up right is one in 10.