Used iPhone - best model?

Need to look for a phone for my SO, he’s really considering a smartphone. I can’t give him my 4s as it won’t activate on Verizon’s network anymore (and wouldn’t work after this year anyway).

I was considering a 6s, but what other used models are worth looking at? I am not as familiar with the 7 or 8 series. I don’t think he’s going to want a super-sized version.

Thanks
Diane

3 posts were merged into an existing topic: Finding a gently used iPhone?