Jan. 5 - 11
Make 5 purchases get 10 bonus stars
Make 7 purchases get 15
Basically only ever order a short ($1.89) Gold Card so free refills.
Never pay for them in the first place as I convert online survey points to Bucky GCs.
The Buy 7 Get 15 = 22 Stars (almost enough for 2 free Venti Frappuccinos.