I would expect that like Spotify, Tidal offline mode has to be renewed by going online within a 30 day period or the files you have saved offline will no longer play. It’s either on or off so to speak, no in between.
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.