I’m pretty sure that Malta has the cheapest Golden Visa Programme.
The New Malta Permanent Residency program (MPRP), known as “Maltese Golden visa” was launched on March 29, 2021.
You only have to pay 100k euros (one time Govt fee as donation) under renting option. The total cost for families will reach around 130k euro (inclusive of all agency, lawyer fees and rent for one year which is around 10k euro per year).
These costs are not recoverable, it works like one off donation to Malta. But you get schengen permanent residency.
I hope this helps