And I only linked you the abridged version of the thing. Forum formatting was no longer conducive to
housing the guide in its entirety.
Anyway, given the family plan situation and it being Sprint, your hands are considerably more tied. Your only choice given you won't rock the boat is a used/refurb for cheap, price a repair (either a shop or a DIY via an iFixit style teardown - if that's even an option yet or at all, haven't checked how service unfriendly the S7 is), or check to see if there was any accidental damage insurance either through Sprint or a credit card (the latter only if you bought it outright).
If you don't mind giving Windows Phone a try, you can pick up a used Sprint Lumia 635 for under $25 these days off Ebay with a clean ESN, and though Sprint never did an official WP10 update for it, you can ride the stable developer preview build channel bringing it current.... and apparently WP10 runs silky on the thing. I can personally attest to battery life and data usage being quite good on the platform, too... but it's not for everyone. Definitely a practical person's sort of smartphone platform.
As for buying used/refurbished in general, the long short is ensuring the device has a clean ESN and you buy from a volume mobile phone dealer off Ebay, meticulously kept private devices where they'll share the ESN so you can check it, or use a used phone buy/sell service like Swappa.