Feedback from people who don't pay anything is useless if you want to build a business.
Right now OP is making an assumption that his product is useful. It's a guess. Doing the beta for free for a small set of users validates it with small effort.
In fact the first release should be as minimal as possible. Op can charge those users in the subsequent releases.
On the other hand someone who has put their hand in their pocket is going to get a lot of my attention.