You could always drop a hint that if they need another cake some time you would be happy to make one for them. My family always expect me to make them cakes, and generally I’m happy to do that, but as JJMon said, if they thought I was going to charge them for it they would probably buy a supermarket cheap one.
If you make it clear that you would be making it for free I’m sure they would be more than happy for you to bake for them. Either way, as long as you realise there’s nothing wrong with you or your baking, that is all that matters xx
karen,Gwynedd