Amazon has the Samsung SmartThings ADT Home Security Starter Kit for $94 with free shipping. Includes a hub, two door and window detectors, and a motion detector, and works with a wide range of smart devices. #1 Best Seller in Home Security Systems.
Walmart has the Chimney Free Infrared Quartz Electric Space Heater (several colors) for $50 with free shipping. Features 5,200 BTUs, heats up to 1,000-square foot room, measures 17.5" x 10.1" x 23".
Amazon has the 2-L Seachem Prime Aquarium Fresh and Saltwater Conditioner for $40 with free shipping. Has excellent Amazon Reviews.