I am using the $15 plan but did a quick hack to use the SimplySafe fob for remote access.
Two relays are used to jump the buttons (Away and Off) on the fob, and the relays are controlled by NodeMCU by following
Then the fob can be controlled by HTTP POST request. One way to do that in Smartthings is to use the HTTP button:
Then I can use a single virtual button to arm/disarm SimpliSafe. I integrated it to my daily routines (Goodbye, I’m Back, Good Morning, Good Night), and use the smart app in this post to check the status(thanks @tobycth3). I’ve tested it for more than one week, and it works great.