Some founders fear charging their users for their product early on. I think it happens out of fear that it's premature & worry it might demotivate them. But I think it's much worse to toil on the wrong thing & waste precious minutes of your life. Use Venmo/PayPal & test!

Providing a free product isn't sufficient to test the value of what you're building. People will lie to you & it is hard to estimate the importance of a problem even when you talk to users. So, let money talk.

Early on with Mixpanel, I charged our first customers using PayPal. I didn't even have a UI. I'd just ran SQL queries for customers & messaged them interesting things I learned about their data. Then, once I had a UI, I charged more! That's when I knew it was valuable to someone.