If you don’t charge, it’s not a pilot.
It’s an extended demo.
Now, that’s better than nothing. It’s something. But a free demo is fraught with issues. Most importantly, the feedback you get is often radically different from free “customers” than paying customers.
You have to start somewhere. Getting someone to use your product is better than no one using your product.
But getting someone to pay something to use your product is 50x better still.
The feedback is 10–100x more honest and real when there is money attached to that usage.