Starbucks to trial 5p charge on disposable cups by The Good Shopping Guide | Jan 12, 2018 | Ethical Shopping Blog | 0 comments Starbucks has announced that it will trial a 5p charge on disposable cups across its London stores, following increasing pressure by MPs. The trial is set to last months, and its purpose is to assess the effectiveness of a charge on disposable cups. This trial will operate in addition to a discount that Starbucks already offers to customers who bring their own reusable cups. Currently, the discount is set at 25p, which is the same as Costa. However, Pret announced recently that in order to encourage more popular use of reusable cups the company is increasing its discount to 50p. Read more.