Most people say Den of Angels is a good starting point. Depends on what you wanna collect though, and I hear they aren't too keen on certain types, brands, and whatnot.

If you're looking for some resources to get a cheap entry model, try http://www.junkyspot.com/

I've seen them at cons, and they're really nice. You can get a 23cm Obitsu doll for pretty cheap, and if you MUST have a 60cm, they have those too.

Of course, there is always Volks USA, though most of their stuff costs a pretty penny. However, they DO have the parts you can use to make replica Rozen Maidens.

Speaking as a dollfie noob myself, I think what I would do is get a 23cm Obitsu for about USD20, and use that to learn the basics.

Thank you so much. I'll certainly take a look around.

Yes, Den of Angels is a really good start.

There is a really great list of links on this page:
http://www.denofangels.com/forums/showthread.php?171927-BJD-Company-Links

Good luck, and have fun in the hobby!