Is the price right?

Today, wife and i are having a yard sale. this is a one-time event in the last five years. All the junk my wife has bought for ebay and never sold, is up for grabs. We differ on the price of one item and its price tag. It’s a Casio electronic piano keyboard. It belonged to our grandaughter and used very little. Still in the box. Its not a toy, it’s the size of a small piano. Works perfectly. I suggested a selling price of $75.00. She thinks that price is too high. Question: What is your opinion of the selling price of this item?