This question never gets old and it's impossible to answer specifically because each transaction has it's own variables. The quality and speed of your work/the quality and cost of the materials used/the target market?
They all have a bearing. Added to that, the reason for making the item plays a big part. Is it simply to make money? How much altruism is in you? In this case some people might relish the opportunity to pay back some of the kindness already shown. If it were me I wouldn't charge her a penny and there's always the hope that I'll get all or part of the cost back on the surplus five yards. Which is puzzling in itself! Why not not buy the right amount? I'm sure there are suppliers who don't just sell whole sides, especially when told it's a gift for a carer.
Of course if you're the sole supporter of six kids who haven't eaten for two days or the recipient has the kind of money that allows them to tip that amount to the doorman at the theatre, the picture changes somewhat.