Kmart doesn't have a huge selection of handheld vacuums; it is either the dual purpose Wet & Dry Vacuum, the Compact hand vacuum cleaner, or the Mini Vacuum Cleaner. While they are all somewhat similar, they all have different purposes.
The Wet & Dry is angled towards both wet and dry messes (what a surprise), the Compact is for small spaces while the Mini is for detail work. Ultimately the Mini and the Compact are pretty similar, but the Compact will be able to handle more.
The Wet & Dry Vacuum has a water capacity of 120ml, and a dry bin capacity of up to 700ml, while the Compact Hand Vacuum has a capacity of 180ml max, and the Mini has just 60ml. They have respective battery lives of 20, 25 and 15 minutes, and ridiculously long charging times for the battery capacities. The Wet & Dry requires a 6 hour charge for those 20 minutes, while the Compact Hand Vacuum takes between 4 and 5 hours. Neither have much on the accessory front either, with just two extra nozzles to get into harder to reach areas.
Although the prices are low, many buyer reviews mention poor suction power on both the Wet & Dry and the Compact models. The Compact has only 4000-5000Pa which is about the same as a cheap robot vacuum. Fine for surface level debris, but not great for getting into the crevices.
The Mini Vac may be the smallest, but it is kinda dual purpose as well. Apart from the vacuum part, it also comes with a blowing nozzle that attaches to the fan end of the vacuum which you can use to blow dust out of small spaces instead of sucking it up.