I joined after this time frame, but when I signed up there was a difference if you brought your own phone or purchased a new one through visible. If you used and old phone it was $50, if you purchased a new phone it was $100. In my opinion the promotions are/were kind of confusing. It seems the phone promotions are only for if you sign up for a new service along with purchasing the phone. They are not just for purchasing a phone with an existing visible plan.
I wish the promotions were a little more clear in that you had to do both to get $100 (purchase a certain new phone from visible and sign up for new service). And if you bring your own phone over with new service it was $50.
It took me a while to figure that out. 😉