I’m looking to add a temperature sensor for my beer fridge. Any suggestions on a good, relatively inexpensive sensor? Thanks.
i have been using the sometimes very cheap visonic sensor in a thick ziplock clear pouch. which the battery will drain down fast due to the cold temp it will last at least a year.
What country are you in and what model hub do you have? The device selection does vary somewhat. 
US… I have the smartthings hub v3