11 months left, the only line that might be eligable is the primary.
that $100 discount, is ONLY EVER available on the primary. ONLY after 22 months.
yes you can get a new phone from ebay or somewhere and put it on your account. corporate stores will charge $20 to do it, along with some retailers. calling CS, they will also charge you $20. my store does not, we do it as a courtesy. also transfering your phone book over at corporate/most retailers is a $10 fee.