Bundle Stars is a UK based Key Distributor for the Steam Platform currently running a massive sale on Skullgirls. While Steam itself may not be running any sales on the Lab Zero fighter, if you head over to Bundle Stars’ site you’ll find that all SG content considerably marked down. That includes the base game, 2nd Encore expansion, DLC characters, and color palette bundles.
The only SG related products you can’t seem to get right now are Big Band and Squigly, both of whom are sold out at the time of this writing.
Source: Bundle Stars