Never asked me for 50/month?

I bought it at full price and it never asked me about 50/month... Did I miss something?

I did the same thing. I figure I'll just return it (and pay the $35 restocking fee) if it turns out I can't use it to replace my old phone on my existing plan since I don't have an upgrade yet. So the worst case for us is that we are out $35 to return it (I hope)