1) Create a product with a special price that is valid for a period (fill the start and end date fields).

http://support.themeburn.com/wp-content/uploads/2016/11/step_1.png

2) In Page Builder use any of the product blocks (Best Sellers, Latest, Featured etc.)

http://support.themeburn.com/wp-content/uploads/2016/11/step_2.png

3) Edit block settings and enable

http://support.themeburn.com/wp-content/uploads/2016/11/step_3.png