Ah, I'm not sure them. I play the game from the Uber launcher (i.e. not linked to steam). I'll ping @mkrater for you, hopefully you'll get an answer when they're back in the office (not sure if in tomorrow or Tuesday, it's a bank holiday in UK tomorrow, don't know for USA though).
Well, I think it goes like this: If you run PA through Steam, it will use Steam to buy commanders. If you run PA outside of Steam, it will use the in-game payment method instead. To start PA outside of Steam, just launch the PA.exe manually.
Yep, you can purchase commanders from the Armory without Steam but launching the local pa.exe file and logging into your account. When you add a Commander to the cart and checkout, you can complete your purchase using a credit card or PayPal which will register the commander to your account and allow you to play with it on or off Steam.
