The standard of living in Jacksonville is pretty low compared to most large cities. Rent prices range greatly, but can be as low as $500 for a one bedroom to $2,000 for a luxury two or three bedroom apartment. It really depends upon what you can afford and what type of amenities you are looking for.
Food and drink prices are much lower than large cities like Miami, and most bars and restaurants run cheap specials different nights of the week.
Utility bills average around $100 a month for smaller apartments during the cooler months, but summers are pretty hot and you will find running the AC gets expensive.