For example Chicago-Las Vegas-Chicago!
Frontier Airlines just started 1-day promotion for flights from/to several US cities. Tickets from 15 USD/12 EUR one way and 30 USD/24 EUR round trip!
Chicago to Las Vegas, Miami, Tampa.
Miami to Chicago, New York, Philadelphia.
Philadelphia to Miami, Orlando, Tampa.
How to book:
If you’re looking for a cheap accommodation you should compare hotel rates on HotelsCombined.com. Don’t forget to read hotel reviews on TripAdvisor.