Fans of Starbucks frappuccinos will be able to buy one and get a second one free during a promotion the company is offering on June 29.

The offer is valid beginning at 3 p.m. at participating Starbucks stores across the United States, the company said on its website. Customers must buy a grande or larger frappuccino or espresso drink to receive one of equal or lesser value for free.

Customers who have a registered Starbucks card are already eligible for the promotion. Customers who do not must sign up for a card here. After filling out the information, customers will receive a promotion code to take advantage of the buy one, get one free deal, Starbucks said on its website.