Based on my one trap out it would take some time. Set up could be fairly involved depending on where the hive entrance is. Then once you start the trap out you have to keep an eye on it to make sure they haven't made another entrance. If it's a big hive you will have to change or add boxes at some point. If you are baiting with eggs you will have to make sure they make a viable queen if the process goes on for more than a month, and do something about it if they don't. Then when it's finished you have to tear down and remove the hive stand/scaffold and hive.
So, if you are going to do it as a service for pay, it really shouldn't be very cheap. At best it will probably need to be several trips. I don't think it's worth doing just for "free" bees. It is worth doing just for the experience once or twice - to me. If I get confident in my ability to complete the job effectively I will probably offer it as a service since I'm a contractor anyway. In the future I will probably fumigate the cavity with sulfer (or something like that) when I believe that the hive has been robbed out. So add that to the list of expenses.
If you are doing removals as a service though the fact that trap outs are non destructive reduces the total cost for the customer - maybe by thousands of dollars. In a lot of cases I doubt if you can really guarantee complete success.