A:AnswerYou should definitely be able to use both. I used trade in credit from my iPhone 5 to purchase the iPhone 6, and at that time they were having a deal where you got a $200 gift card with the purchase of any open box iPhone 6, and another deal where if you upgrade to an iPhone 6 you got a $50 gift card. Best buy let me use all of the gift cards and credits towards the purchase so I actually ended up making $40 in gift cards after everything. So they should let you stack them :)
A:AnswerCharge it until it says "100%" on the battery icon on the top right corner of your screen. You may have to change your settings for this (Settings> General > Usage > Battery Percentage > ON )
It usually will take 2-3 hours to go from about 5% to 100%.
A:AnswerYou can get a 2 year contract, but if you do so under the $99 offer, Verizon charges $40/mo for line access charge. If you compare that option to the lease, you pay the same amount after 2 years. The lease is actually a little cheaper by about $90.