I am not in the US. I don’t like to buy second hand smartphone in my country. It is either overpriced or straight up junk, be it in the local equivalent of craiglist or in specialized store. However, It is the solution I would prefer if I can get a spare phone from someone I know (given or bought). But I have not been lucky yet. Most people I know use their phone untill they stop working or there is no sd card.