Season is the week. You get 30 packages, which at 20 tokens per package is a total of 600 tokens needed. After you reach your limit, you will just get the same faction shader over and over and over. I seem to remember last time that they gave you an additional week to turn in tokens after they stopped being given out in the first week, but i had all mine turned in already by that point. I have 100s of that damn shader. Some people are reporting they are getting only shaders prior to hitting 30 packages, but who knows how accurate that is. The announced limit is 30 for the entire weekly event (or two week event if you count the week that you can't earn tokens)