Yes there are! The middle of the week is usually better than the end, or beginning. Winter is better than summer for lower fares. Flying later at night, earlier in the morning (the red eye). There are many factors that companies consider when setting prices. Availability is probably the number one. If no one wants to fly on certain flights, the airline will adjust costs to entice flyers to book during that time frame.
Check out these links for cheap flights:
www.selloffvacations.com
www.lastminuteclub.com
