This is a really great question. The answer to this is that it’s hard to tell the difference between real and fake. But there are some things you can look for when buying one.
The first thing I would do is go on YouTube and type in 3 year old playing piano or some other similar search terms. Most of the videos will have comments, which means they’re most likely fake because people don’t like to post negative comments about their children’s abilities or play around with them too much.
Another way to see if it’s real or not is by looking at the seller’s reviews on eBay and other places where people sell stuff online. Usually, a lot of people who bought this item will leave positive feedback, but only one person left a negative review. If that person is an actual customer then it’s probably a good deal because most people who leave negative feedback aren’t actually customers (most of them are just jealous).