Hi! I am a private French tutor on Skype and I am thinking about offering a special offer for students that take many lessons per week. For example: " 60 minutes: 24$ (or 20$ if you take three or more lessons per week) " However, I was wondering how to deal with the potential "complications" that could arise from this. For instance, what if they book three lessons at 20$ each, complete two of them, and end up having to cancel the third one. Do I ask them to send me 8$ to make up for the price the other two lessons are supposed to be? Do I keep 8$ from the 20$ and send them a 12$ refund? Is that special offer even a good idea to begin with? I know this might sound like a dumb question but I'm simply trying to figure out what is the most simple and logical way to make it work. I haven't been in this field for very long. What do you think?