Starbucks rewards are currently running promo when you start a new rewards account /card they put 13 stars on it when you open account. When you have 15 you get a free drink. Every drink or item you buy gives you 1 star. If you're buying 2 things buy on separate transactions. Therefore you only need to buy 2 things such as tall filter coffee using own mug for 75p. Minimum top up on rewards account/card inshore is £2 whereas online it's £10.