Can i avoid paying the $12.99 fee for Spotify on my iphone?

I signed up for my original spotify account with an in-app purchase from my iPhone using facebook to log in i'm still on the free trial but apple charges a fee so you pay $12.99 a month. NOW spoitfy has this 3-month 0.99 trial and a $9.99 membership and i want in! So i created an account directly with spotify. I unsubscribed from the spotify itunes account BUT i'm worried that if i log into the account on my iphone app it will charge me the apple price. How does it work?

Spotify is a different company, Apple has nothing to do with it.