Used Salsa Journeyman 700C Flatbar - Claris Group

A Swiss Army knife of a bike. Has a slightly knobby tire that is nice and wide, so you could drop the tire pressure and ride the sandy boardwalk or fire roads with confidence. Meant to be an on road / off road bike, this is going to be much more durable for city commuting.

Medium
Salsa official size recommendation is 5' 8" - 6' 0" but I think some 5' 7" folks would be comfortable and I think few six footers would find it large enough.
$850