Systems, devices, and methods are provided for monitoring and tracking an item in a controlled space. In one embodiment, a portal system that monitors the controlled space includes a radio frequency tag that is attached to inventory and a portal device, which includes a computing device, a receiver and a locking door. The receiver is configured to receive a signal from radio frequency tag, and send the signal to the computing device. The locking door is coupled to the computing device. The computing device is configured to verify whether the user is authorized to be taking inventory in and out of the controlled space through the locking door based on the received signal, and to unlock the locking door based on the received signal. The computing device has a database that includes the total value of the inventory that the user has taken out of the controlled space. The computing device determines whether the user have exceeded a threshold value of inventory based on the total value of inventory that the user has taken out of the controlled space, and provides a notification signal to an administrator based on the total value of inventory.