Buying citizenship: Which nations are affordable?

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There are plenty of countries offering to hand you a new citizenship, provided you invest a sufficient amount of money. For those who do not have millions to spare, which nations are more affordable?

Malta made headlines earlier this week when its parliament approved a program to sell the nationality for just $900,000. It comes with full EU benefits and is one of the least restrictive passports for global jetsetters.

It's likely to be an unwelcome development for an immigration-wary Brussels. Programs are already available for swift residency in Portugal—a "Gold Residence Permit Programme" there can be secured with property investments of at least $675,000. It does not give you full citizenship, however.

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Earlier in the summer, Ireland reduced its minimum investment requirement by 50 percent; it now stands at $675,000 as well. It gets you a residency and, if you are patient enough, an Irish passport five years later.

A better deal is on the table in Latvia, where a five-year residency can be locked in for just $96,000. It gives you access to the nations of the Schengen Area—a common visa policy shared by 26 European countries. That privilege may be brought to an end soon given growing Latvian political opposition.

Still, within continental Europe, Bulgaria is on the list with full citizenship for $500,000, according to the OECD. Macedonia's scheme costs the same (and you need to employ at least 10 people), the U.S. State Department said in a report.

Demand for alternative citizenships has grown partly because of the turmoil in the Middle East, as wealthy families from Syria, Libya, Egypt and Iraq, among others, attempt to safeguard global, more visa-free mobility.

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Passports in countries that are still stable in the Middle East are almost impossible to get. Although rarely publicized, some have been given to those who have made significant contributions to the nation over a long time. Bahrain has historically been more lenient. In Dubai, part of the United Arab Emirates, a residency can only be applied for when purchasing property in excess of $273,000.

One of the easiest in both process and universal practicality is the tiny, tropical Eastern Caribbean spot of St. Kitts and Nevis. All that's needed is a real estate investment of $400,000 (only villas and condominiums qualify) and a registration fee of$50,000. And you get to travel to 131 countries visa-free, according to the Henley & Partners Visa Restriction Index 2013.

There are other options. Last month, the Caribbean island of Antigua and Barbuda launched a "Citizenship by Investment Programme." A $400,000 real estate investment helps you pass through the borders of 130 counties without a visa.

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There is also the Commonwealth of Dominica. Here you will need a non-refundable investment of $100,000, in addition to $1,800 in fees. It takes eight weeks for the "economic citizenship" to be granted. Expect to travel to 87 countries visa-free.

If you are completely cash-strapped, there is always Paraguay, which offers citizenship for a nominal fee to those who have resided in the country for at least three years. Or Spain, where marriage to a Spaniard is needed for just one year.