Breaking lease early - what is reasonable for assisting?

[Andrea Minnillo]

Renter is breaking lease 5 months early.   They want us to pay half of the realtor fees to list/show our rental property when they move in 2 months.   We have declined to pay anything for this service.   

What we think is reasonable as landlords (state of Ohio) is to call local colleges, prepare the craigs list ad, call local network for renters, etc..   But paying a large fee to realtor in a highly rentable area long before I had planned to re-rent the property is not reasonable.   Thoughts?