Sincerely think you are overvaluating this service subscription price. There is little justification for users to spend this much. Nostr just is not as popular of a social network at this point in time for this to catch on and be cost effective. My suggestion is $4.99 - $19.99 MAX. Otherwise you will only have a couple dozen hard core users willing to pay this highly unreasonable price. We live in a world full of subscriptions. While this provides value and fills a definite need. You must also be realistic about your expectations and set your price according to what your audience is actually willing to pay. Not what you are hoping they will pay.