What phone can I use with my Sprint family plan?

[AC Question]

I am currently looking into buying a new smartphone, but the thing is I am kind of out of the loop when it comes to phones. I am not sure if a particular phone will work with the Sprint family plan I am on or not. From what I have read when looking on Amazon, unblocked phones wont work cause they are GSM while Sprint phones are CDMA, so I look for Sprint phones, but the ones I find interesting are prepaid. Will I be able to put a prepaid phone onto my family plan?

Unfortunately I can't post a specific link, but an example would be search Sprint Sharp Aquos Crystal on Amazon.