There were a few reasons why I chose to say 'This product is not yet available yet' rather than sell it. First, I was going to do a full product launch and didn't want to release the product into the wild yet. Second, as comments stated below, if one person bought it at $100 and realized someone else bought it at $5, they would be angry. They would ask for their money back. If I were going to eventually charge $50 for the product (which I did), the people who bought it for more would be pissed.
You could give it to all your first customers for the lowest point offered. That is, they said they would pay $60 but you only charge them $20. Tell them why. Tell them this is basically an introductory price and it will go up, but because they helped you they are special. Of course, this limits the N you get for your testing, but it gets rid of the ickiness of it all.
