Entry level turntable for my son

Marantz TT-15S1, great value!

Used Technics except for ones with a Plug in Cartridge.

1. Does your son prefer a belt driven TT or DD?
2. What is your budget?

I wouldn't buy any used Technics SL1200, because those were used and abused by DJs years ago. It's hard to find one that was used as a home playing TT. If your son prefers DD, I would go with a NEW SL1200G if you wouldn't mind to spend over $1600 or New Pioneer PLX1000 for around $800. If he prefer the classic one my choice would be much wider: U-Turn, Pro-ject, Music Hall, Rega Planar 1, Marantz. They are all in a same price category of $350-$500 with a similar performance. Sometimes I even think they a produce at the same factory :)

Steer clear of "Toy" tables. I picked up an AudioTechnica AT-LP60 used for like 50$ off a friend (they retail at Best Buy for like 149 or something). It worked OK when I was using my HT receiver, but sounded miserable once I finally got around to upgrading to a real high-end amp. After that I picked up a Denon DP-300F. That actually sounded REALLY good. It was fully automatic and had a built-in preamp and lasted me until I picked up a really nice Emotiva differential with a built in Phono stage. Gave that one to my parents (who say it sounded better than the turn table they had growing up!) and grabbed a used Pro-Ject Debut Carbon used for like 350. It is incredible! Highly recommended and super affordable. Plus, it's rife with mods and extras to really geek out on.