Correct. I got $10 off (using a referral code) Demon Days when I signed up since I didn't use it on anything else.
Don't know.
I'm not 100% sure, but it appears I can still cancel before I get charged for Tidal on May 2nd. I've listened to it 3 times and I'm still not sure if I want it, but I have liked it more these last 2 times.
Don't know this either. I got a use of my referral code and spent the $10 on the Methyl Ethel album in the store.