Low thousands (or very high hundreds), perhaps. It’s still one fairly heavy outdoor unit, a moderately bulky indoor unit, a pump, two radiators, insulated pipes and control wires between, a circuit (wiring and an overcurrent device) and a disconnect, and a couple hours of labor from two tradespeople.

That’s unlikely to be sustainable for an out of pocket of a low hundreds figure.

You can buy a new Samsung mini split today for around $200 in asia, so with tax and shipping let's say $300 max. These things are mass-produced in the hundreds of millions of units. They're cheap and plentiful.

Obviously the installation will be more expensive in Europe due to higher wages, but the units themselves should be dirt cheap.