It looks like two sites are having major sales on Deep Silver's Saints Row series. Both Humble Bundle and GOG.com have the series for about 75% off, and you can either pick it up as a large bundle deal or piecemeal with the same savings on either site. Humble Bundle will be giving you Steam codes for the games, while GOG will let you download them DRM free.
If you pick up Saint's Row VI and it's DLC Gat Out of Hell on GOG before the end of the night, you get a free copy of Saints Row II. Or you can just pick up the whole series together on Humble Bundle.
Really, the decision is going to come down to time and how much you love Steam. If you prefer a more DRM-free experience, GOG is definitely the better bet. But, Steam is a popular gaming platform for a reason.
Players who already have Saints Row on Steam can use GOG's connect service to link their Steam account and play the games DRM free.
Personally, since you can just buy the other Saints Row games on GOG and still get Saints Row II free, that might be a little bit cheaper than the Humble Bundle. But if you love to game on Steam, well, less than $13 for the whole series is a steal.
Humble Bundle and GOG also have sales on other Deep Silver titles like Mighty No. 9, Homefront, Risen, Dead Island, Ryse: Son of Rome. The Humble sale ends Sunday. The GOG Deep Silver sale ends in six days. But let's be honest, if you're picking up any Deep Silver game this weekend, it's going to be Saint's Row.