75k in Phoenix can be livable, but "comfortable" depends on your definition and spending habits. Housing is the biggest factor. You can find decent apartments outside the downtown core for around $1500-$2000. Factor in utilities, transportation (car recommended), and groceries, and you're looking at roughly $3000/month in expenses. That leaves around $2000 for savings, entertainment, and other expenses. Negotiate higher if you want more breathing room or plan to live in a more desirable area.