In the TV series Edit
Beth is portrayed by Kristen Gutoskie.
A Martha affiliated with Jezebel's, she is first seen at the brothel trading with Nick bottles of alcoholic beverages and additional contraband for other illicit goods, such as prescription drugs and pregnancy tests that are used by the customers or working girls of the brothel.
She is (or used to be) in a sexual relationship with Nick, who refuses her advances because of his interest for Offred.
Beth was a very talented chef in her past life, mentioning her pesto recipe got her a James Beard nomination after getting fresh basil from Nick.