I'd consider myself a newbie as well, so hope I can help.

For a vendor, I'd suggest [link=http://rcscalemodel.com/]rcscalemodel[/link].

For a beginner tank, I'd go with a Heng Long, as they are cheap, but work well enough to decide if you want to go "all out" and pay the Tamiya $$ for the ultimate, or just buy more Heng Long's. I'd strongly advise getting metal gearbox, and the metal track upgrade, all available at the above site.

Be aware Heng Long has released a StuG III, and should be available for sale shortly, if you like the looks of it, or intend to do IR battle.