I'm trying to cut down on the electrical use in a condo and I rarely use hot water. If I turn off that breaker, will there be any harm done to the hot water heater in the long run compared to the amount of money I will save on electricity.

There would be no harm to the heater by turning off the electricity. Depending on what you mean by "rarely use hot water" you may or may not see any cost savings. If you mean once in 24 hours you may see some small savings. If you mean once every 5 hours you probably won't see any savings. The cost of maintaining a tank of hot water is determined by the heat loss rate of the water heater. Water heaters are very well insulated.