Don
What do you recommend getting out to? I don't mind paying for something.
As it1uk suggests, it depends what gameplay you are after. There are a lot of different playstyles, but to start with the basics the first three nations had distinct specialities:
Russians - The Brawlers. Some Chinese tanks are pretty good at this too, but in most cases, the Russian tanks are better.
Germans - Some of the best snipers in the game, a lot of the time with some reasonable armour to back it up.
US - A mixture of the two, jack of all trades. They often have strong turrets with good gun depression.
Maybe give most of these nations a try at the lower tiers. To start with as a line to grind I would recommend the russian mediums, going from the MS-1, up through the T-60, T-70, T-80, T-34, T-34-85, T-43, T-44, T-54 and finally either the T-62A or the Object 140. There are not many stinkers in that line (T-43 will be touted as bad, but it's really just more of the same of the T34-85, so not bad per se, just samey) so it is not a bad line to play through.
As far as paying for anything in this game, I would not recommend anyone does so until they at least get up to tier 6, then if they enjoy the game still, pick up a tier 6 premium such as the Crowmwell B, T34-85 Rudy/M or whatever else suits them. If you are going up the russian medium line, one of the T34-85 premiums will do nicely as a crew trainer (along with your current T29).
Finally, prepare for a salty community. There will be some people happy to help with advice, but most people complain a lot and blame team mates whenever they die. If you want some advice once you have got the hang of the basics, feel free to ask in here any time.