Mini sauna covers three quite different products at three price points, and the listings rarely make clear which you are looking at. One of them is a real cabin, one is a tent you sit in, and one is a bag you lie in. All three will make you sweat. Only one of them is a sauna in the ordinary sense.
The sauna blanket
A padded, heated sleeping bag with your head out. It warms your body by conduction and radiant heat and will certainly make you sweat. It is the cheapest of the three by a wide margin and it stores in a cupboard. What it is not is a room: there is no air to heat, no steam, and nothing social about it.
The folding pod
A fabric tent on a frame, usually with infrared panels, often with a zip your head goes through. More room than a blanket, still no meaningful air temperature, and it packs away. Good for a small apartment. Read the specification carefully, because the ones with your head outside are a different experience from the ones you sit inside entirely.
The single seat cabin
A rigid one person infrared cabin, around three feet square, that runs on a normal circuit and looks like furniture. This is a real sauna: an enclosed room you sit in with a door and a bench. It costs several times what a pod does and it does not fold away, but it is the one you will still be using in five years.
Which to buy
Buy the blanket if space is the binding constraint and you mainly want the sweat. Buy the pod if you want a slightly more sauna-like session and might move. Buy the cabin if you have a corner for it, because the gap in how much it gets used is larger than the gap in price suggests.
Questions people ask about mini sauna
Is a sauna blanket a real sauna?
It will make you sweat, but it is not a room and there is no heated air or steam. Judge it as its own product rather than as a small sauna.
What is the smallest real cabin?
A single seat infrared cabin, around three feet square, which will usually run on an ordinary household circuit.
Do folding pods get hot?
Not in the air temperature sense. Infrared warms your body directly, so the enclosed air stays mild even while you sweat.