the M56 Scorpion is being sold on EU for 50 Euro as a part of a "special" collector's bundle. Keep in mind Wargaming's policy to sell overpriced bundles as "limited" an introducing the same vehicles for less price a couple of months later (or sometimes even for free as a part of some event).
The M56 Scorpion was originally supposed to be a regular US premium TD and started on tier 8 - after a while it was rebalanced to tier 7. It has a solid gun and mobility but literally no armor at all and whether it is actually balanced or not is... questionable.
In any case, if you feel like spending 50 Euro on a tier 7 vehicle, share with us your experiences!