On the payment page if you click “continue” you are taken into the main part of the app where four sessions are currently completely free for you to try. These sessions will give you a good idea of the quality of all of the sessions. You can also access a free trial on the yearly subscription option. This unlocks all sessions and as long as you cancel within 7 days there is no charge. The other option is simply to purchase knowing that on Apple and Google you can always claim a refund within 14 days if it turns out the app is not for you. See the other information on this page about how to go about managing your subscription or claiming a refund.