Those are early adopters, not volunteers. They pay to have their problem solved. If they're not happy to pay 5$ for it then it's either not the right customer or not a real problem.
We only charge you one time, then never again until a month after it leaves beta. This just locks you in at the discounted price and doesn't charge you again until the 2nd month out of beta. I'll make this clearer on the site.
As far as why we are taking money, we already started a private beta and are looking to get feedback from paying customers. As incredibly useful as our private beta users have been, they aren't paying so it is hard to determine what things they ask for are things they would pay for and what are just neat things they want. With paying users it is a little clearer that they would pay for feature x, because they are already paying to use the service.
https://zapier.com/blog/anatomy-of-sale-or-how-andrew-warner...
2)Are you really gonna take money from people helping you in private beta ? I mean its good to give 50% off but these will be your first customers and will help you shape the product. I can understand you might have done this after a lot of thought, but you still owe these people for every criticize they make.