Short version: Should I buy; T1 Heavy, KV-1, Pz IV H or VK30.01H and why?

Long version: Idiot noob player who has stupidly ground up to tier 5 along too many tech tree lines. Finally have enough xp but barely enough credits (f2p) for one of the tanks listed above. Still utterly rubbish in battle so unlikely to make a significant dent on my appalling stats but it’d be nice to make credits a little quicker.

All advice very gratefully received. Advice here and on line is great at pointing out the pros and cons of all these tanks but in the real world?..

Thanks…