Charge From Day One
Free is the enemy of learning. A company using your product for free tells you nothing about whether you've built something valuable. Payment is the only unambiguous signal, so charge from the first customer, even if the price is small and half made-up.
Price is an experiment like everything else. Ask prospects about budget and what they pay competitors, then test numbers. Founders almost always undercharge. If nobody flinches at your price, raise it. Counterintuitively, higher prices often close better, because a real price signals a real product and forces the buyer to take the evaluation seriously.
Free pilots deserve special suspicion. A prospect who won't put any money down usually isn't a buyer with budget, they're a browser being polite. Even a heavily discounted paid pilot with a defined conversion date keeps everyone honest in a way free never does.
Key idea
Payment is the only real validation. Charge your first customer, keep testing higher prices, and prefer paid pilots with a conversion date over free ones.