Bulgaria, has its own official immigration policy and law. Depending on the objective, it can be a nice place to have a low cost, low tax base.
The immigration process is straight forward and simple.
If you are wealthy, there is a citizenship by investment option.
If you are looking to just settle down on a long stay visa, the cost is much lower.
Here is a good link from the USA Library of Congress outlining the options and linking to the relevant laws.
Since 2001, there have been roughly 116,000 foreginers, who obtained a long term residency or citizenship based on the immigration laws.
here is the source info:
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thanks for reading.