Im only new at this as well, and am still in the hunt for a machine, so you will probably be better off relying on any advice from those more qualified than me to give it, but heres my second crack anyway....
If i were in your position and had about $600 to spend, i would try and stretch it a bit and get a Sunbeam EM6900 and Sunbeam 0480 (i think thats the code, not quite sure) Grinder.
Operating on "best prices", ive seen teh EM6900 for $499 (check the For Sale section of this site, and it has a link to where it was available for that price), and you can also find the grinder online for about $150.
So that puts you at $650, and from various reviews of the EM6900, its going to give you a machine that punches well above its weight.
However if you intend to upgrade at a later date, you may be better off spending the extra money on a good grinder instead, and just getting a cheaper machine for now. As a better grinder is going to last you a very long time. Something like a Rocky may fit your price range, and then maybe go for a cheaper machine.