Looking for recommendations for nice Frankfurt hotels that don't cost $500-600 per night. Thanks in advance.

Finding places for cheaper should be easy. It totally depends on your plans, mode of transportation and the clubs you want to visit.

If you are going to be there mainly for clubbing and rely on public transportation, you might want to stay clos to Frankfurt Haubtbahnhof (main station). There are dozens of hotels, for as little as 30 euro a night. Booking.com will give you a good overview. Sticking to Ibis or Mercure hotels might also work well.

Thank you for the info. I'll be there for clubbing & relying on public transportation.

Sorry for late reply Hotel Arosa is good basic hotel no frills, cheap, don't get bfast as I slept through times, but clean & access to trolley across street.