This will be my first time to ever charge someone for my cakes. My boyfriends mom wants me to make a simple barrell cake for Thanksgiving, she's gonna pay me for all the ingredients I need. What should I charge her for me making it, or should I?

Most professional decorators charge by the slice/serving (usually 1x2x4). Since it's their business they need to make a profit above and beyond covering the cost of their ingredients since they have many other business related expenses...

If I was a guest at the Thanksgiving dinner, I would bring the cake as my contribution to the celebration and just enjoy the oohs and ahhs.

HTH