Spotify premium price odd occurrence

Excuse the weird wording in the title didn’t know what to call this question I have. Yesterday I bought Spotify premium the “$9.99 3 months Spotify premium.” I bought it on my phone on the website with my paypal account. Don’t know if that has anything to do with it. Today I told my friend about premium and I searched it up on her phone and the first thing that came up was “$0.99 3 months Spotify premium.” She was able to buy it for 99 cents. Can anyone explain how this happened. I’m happy for my friend but a little jealous at the same time.