Another option is to consider donation during beta phase. Ask users to pay whatever they want (don't mention minimum and maximum). This will provide you some idea about price customers willing to pay and what type of customers value your product.

I recently implemented this strategy for my web service. Only about 1% of registered users and 30% of active users donated but the average donor contribution was three times of what I was estimating the price of the service.

It also helped me prioritize which user requests should bubble up quickly. My plan is now to introduce donor exclusive features. Then I want to track changes in number of donors and contribution.