I've missed any mention of simply adding a line to your current plan for the new iPhone and swapping SIM cards or numbers w/ your existing phone. Assuming that you are upgrade-ineligible and have 16 months or less on your contract, that should come out cheaper than paying the extra $200 early upgrade price of 399/499. The way I see it, it should cost a $36 activation fee + ~$10/month for the extra line. (10*16 + 36 = 196). The less time remaining on the existing contract, the larger the difference. Will they not let you reassign phone numbers to different phones on your account? Will switching SIM cards after the fact have the same effect, or is there some tie between a particular iPhone and a particular SIM card?