A:Answer It's exactly the same as walking into a Sprint store and upgrading your phone. Best Buy works with them, so it acts the same. They activate the new phone after looking up your Sprint account and transfer it to your phone number. You have the same options you would at a Sprint store: buy, upgrade or lease the phone. If you want to make monthly payments you sure can, but Best Buy offers some killer deals this month on phones for new contracts or renewals. I just got an S6 for $1 out the door (bought, not leased) for my 2-year upgrade with Sprint (I was also an existing customer).
For transferring data, Samsung Smart Switch from the Play Store is your friend. Download it to your old phone and the folks at Best Buy will start it on your new phone. you click through and select what you want to transfer (photos, videos, ringtones, music, etc) and it takes care of the rest. It even preserved my WiFi settings and password.