With 3K you can get some excellent vinyl sound, especially if you are considering used/demo. Some tables to keep in mind in that range:(buy the table/arm used if you are serious, then get a new cartridge from a local dealer who will help you set up the table :))
VPI HW19
Basis(any)
Linn LP12(my table) w/Lingo or Valhalla power supply
Maplenoll(any)
Goldmund(any) pricey but affordable used
ARMS:
(if buying separately)
Rega RB900(RB300 or RB600 if you are trying to save $$)
SME(most models are awesome)
Linn Ekos or Ittok(one up from my Akito)
Graham(you should be so lucky to find one of these used)
Cartridges - depends on the table/arm and your system/tastes
but here are some strong cartridges and some strong contenders:
Bang for the buck: Denon,Grado,Benz, Linn(I use a Linn K-9 with good results)
Budget to the winds(or depserate seller): Koetsu)any), Lyra Clavis, Linn Arkiv.
Van Den Hull Grasshopper
These are not the only good possibilities by a mile, just some you do not want to miss. I have seen some killer deals on this site, well within your budget.
As for definitions and comprehension, aside from a large book like Robert Harley's, you might want to find a good analogue shop and pick their brains. As I said, you can find a good deal on the table/arm and then give them the very profitable cartridge busines in return for their expertise and set-up help. It is not rocket-science, you just want your arm to track correctly, and isolate your turntable both from your speaker output and any heavy footsteps or accidental bumps into the table. The factors that allow you to pull this off, aside from the basic table itself, are a dedicated turntable stand like the Arrici.
Once the table is set up, it tends to stay that way unless it is moved or seriously jostled. But it is worth it!
Have fun! Read a lot, listen a lot, and shop till the tonearm drops!