I'd love to get feedback on whether you think joining my beta will cost money or not. Is it clear from the copy which it is?
Landing page looks nice.
Honestly, for something like this I'd just focus on getting feedback and improving the service at first. You want the barrier to entry to be as low as possible.
If you have a working product and more than 20 people using it, then start worrying about pricing maybe.
I usually think of beta programs as free. In exchange for providing feedback and guiding the direction of the product as an early adopter I think it's fair to either make it free during the beta period or provide a steep discount for the first few months when the product is no longer in beta. It's not clear to me though whether my interpretation is correct or not when looking at the copy. Clicking around I see you have a page about locking in the price but which price? If I use the free version then is it going to be free forever if I stay within the limitations of the free account?