For Prime members only, Amazon offers this Women's Beauty Sample Box bundled with a $11.99 Amazon Credit for $11.99 with free shipping. (The credit must be used towards select beauty purchases.) Assuming you'll spend the credit, that's like getting the sample box for free. This box contains samples from brands like Aveeno, Crest, Proactiv, and Fekkai.
Note: This item currently has an estimated shipping delay of one to two weeks.