My story is not too bad, only one... I made a train cake...Spent 3 hours on the engine. Was making the other cars when my DH took the engine to put in the fridge, attempted to open the door while hold ...
I always remember the process when judging my cakes and if it was horrible, that is how I see the cake. Remember, everyone else just sees the finished cake, they don't know the horror story behind it. ...
I say... let them make fondant.
Better yet, let them make a homemade cake(s), make the icing, torte the cake with homemade filling, make the fondant, roll out the fondant, then try to smooth the fond ...
For buttercream (and you could use chocolate covered coffee beans as accent)... I would charge $15 like stated above. The design is fairly simple, however, the filling etc. is also a factor