There is various options, but definately you need to learn the basics. You can always get a 7x12 for cheap and learn the basics on that then you will be in a better position to figure out what you need. I started on an old Jet 1024 which was a bit big I believe but I learned a lot. I then switched to a Import 10x18 which was a lot smaller machine. Both the 1024 and the 1018 were capable of most of the work I did but I wanted more. Figured out what my plans were and how I wanted to chamber my barrels from that point on and decided I needed a 40 inch lathe.
I now run a Enco 13x40 which is not a bad machine overall, but I wish I kept the 1018 for smaller stuff. I will buy a small machine in the future for sure. You won't be disapointed with a Grizzly 1340 or any of it's variant, but if you wanna start somewhere a smaller machine is the way to go I believe.
GST