Tidal does not post the cost to buy a song or an album on their site

Seeking to find out about streaming. I know Tidal charges $19.99 per month for listening to  high fidelity music on their site. But what if you want to purchase a song or an album? What is the cost?  There is no phone customer service phone number  that I could find to call and inquire. They do provide "Answers to frequently Asked Questions". I am surprised that nobody has asked the cost to purchase a song or an album. If I missed the information I have requested, would appreciate if somebody who used Tidal could provide assistance.  Thank you.