Buy-Once Meditation and Breathwork Timer

People who already meditate, or who follow a teacher's practice, pay once for a plain timer, interval bells, a breath pacer and a private log instead of renting Calm or Headspace at roughly $70-$230 a year. The category clearly makes money: Calm says it has four million paying subscribers and was valued at $1 billion, and Headspace reports more than $100 million of revenue. The warning sign is that the core job already exists for free — Medito (about 2.8M installs), Insight Timer (about 11.7M installs) and Plum Village all give away timers and content, and users on Hacker News already say they dropped a paid app for a free timer. So a paid one-time timer only stands if it is clearly better for a specific person (offline, no account, custom interval bells, a log that never expires), not merely cheaper. Validation step: put up one landing page offering a $12 one-time pre-order and send 200 visitors from r/Meditation and the Hacker News 'mentally healthy apps' thread; if fewer than 2% pre-order, the free alternatives are good enough and this idea should be dropped.