Questions about promised promotion

I bought directly from T-Mobile. I just found out why I'm not eligible for the gift card. My phone is essentially free, so I'm not eligible for the card. I'm annoyed that the store employee didn't mention this. I've been checking other carriers in the meantime, but not sure what I'll do. I don't trust  these businesses at all (I'm cynical about all business). I must admit, the service through T-Mobile has been good so far. I'm on the $40/month plan, and would like to get a cheaper plan, like other carriers have, but there isn't any cheaper on T-Mobile.

  The fact is that the phone isn't actually free  until about 2 years later; so the company uses that to lock a customer in to their plan. Pretty tricky.

looks like I'll probably stay with T-Mobile, but I'm angered that the store didn't explain things more fully. Nice people to deal with, though.