Cromwell B (around 14€) – https://eu.wargaming.net/shop/wot/specials/6934/
IS-2 (around 20€)- https://eu.wargaming.net/shop/wot/specials/6932/
ISU-122S (around 19€) – https://eu.wargaming.net/shop/wot/specials/6928/
Bundle contents: Tank, Garage Slot, BIA crew.
The Cromwell is arguably worth the price if you enjoy Cromwell gameplay and tier VI in general.
Other vehicles are not worth it imo unless you’re after the BIA crews that come with these tanks. That said I’d be cautious about spending money on these as Wargaming are about to unleash ‘Crew 2.0’ on us in the near future and who knows what unholy mess that will turn out to be.