This is my first post. i didn't see it on a search so . . .
I just bought a lifetime subscription for brain.fm for $39.
I got it off this link
the website itself , is called "tech deals"- If you sign up for tech deals first- then go back in , they email you pretty quickly w/ a 20% discount off posted prices, so you may be able to save a few more dollars. I didn't realize this until after I had bought the subscription. sale price good for 3 more days.
From the brain.fm website: "Brain.fm uses AI and a wealth of neurological research to stream the best background music for studying, sleeping, or relaxation. Give yourself a productivity boost and outmatch your to-do list with Brain.fm. "
suggest you ck out the brain.fm site first- they will let you listen to samples of their focus music. caveat: there's no android app yet, only apple and windows. Android is in development, they say.
makes a good last minute gift , as you get immediate access to the site.