Beginner Turntable

I bought a Thorens TD 145 for $200.00. With a Herbies record mat and Grado cartridge, it sounds pretty good. I would think hard about whether I wanted a good modern table like a Rega or a good vintage table that could be modified like a Thorens.

If your playing classical, a Grado cartridge is a safe choice for a cartridge and they make a number of budget cartridges for those who are just getting started.
I have a Grado mono cartridge as my records are classical mono platters from about 1954 to 1960. I collect Arkiv Produktion, RCA Red Seal, Westminster, London/Decca etc.. and the tone is very rich and even throughout the frequencies/registers.
My records offer a listening experience different from my digital player!
I believe the main thing is to enjoy and have fun.

As far as the best Grado cartridge, it's really up to you to decide because price ranges will vary but if I were to suggest one outstanding Grado cartridge for the money, the Grado Reference Sonata 1 would be the cartridge to aim for. It retails however for $600.00 and my understanding is that this price would currently be out of your range. It doesn't mean however that it won't show up as a second hand cartridge for sale on one of these auction sites.
I'm not real sure about compliance factors as you haven't chosen a table or a phono stage but you'd probably be better off with a high output cartridge.
I suppose if I were looking to buy a cartridge on a budget, I'd pick up the first Grado that I could afford that's being sold as a pre owned high output cartridge but I'd suggest researching on the Grado website before doing anything.
By the way, you'll also need someone to install the cartridge and then you'll have to load the cartridge on to your chosen phono stage. The person selling you the turntable may be able to help you with this.

Hi Lowrider, I have to agree with you that a better table than a USB or entry level modern table might be advantageous in the long run. A Linn or Thorens would provide the chance to make upgrades (i.e. a solid plinth and a better tonearm) along the way without breaking the bank up front for the initial purchase.
Also, turntables are the one piece of equipment that I'd have less hesitation about buying used because they're more mechanical than electrical.