(ANSA-AFP) - SOFIA, 29 DIC - Bulgaria will become the 21st country to adopt the euro on Thursday, but some believe the move could bring higher prices and add to instability in the European Union's poorest country. A protest campaign emerged this year to "keep the Bulgarian lev", playing on public fears of price rises and a generally negative view of the euro among much of the population. But successive governments have pushed to join the eurozone and supporters insist it will boost the economy, reinforce ties to the West and protect against Russia's influence. The single currency first rolled out in 12 countries on January 1, 2002, and has since regularly extended its influence, with Croatia the last country to join in 2023. But Bulgaria faces unique challenges, including anti-corruption protests that recently swept a conservative-led government from office, leaving the country on the verge of its eighth election in five years. The latest survey by the EU's polling agency Eurobarometer suggested 49 percent of Bulgarians were against the single currency. After hyperinflation in the 1990s, Bulgaria pegged its currency to the German mark and then to the euro, making the country dependent on the European Central Bank (ECB). "It will now finally be able to take part in decision making within this monetary union," Georgi Angelov, senior economist at the Open Society Institute in Sofia, told AFP. An EU member since 2007, Bulgaria joined the so-called "waiting room" to the single currency in 2020, at the same time as Croatia. The gains of joining the euro are "substantial", ECB president Christine Lagarde said last month in Sofia, citing "smoother trade, lower financing costs and more stable prices". Small and medium-sized enterprises stand to save an equivalent of some 500 million euros ($580 million) in exchange fees, she added. One sector expected to benefit in the Black Sea nation is tourism, which this year generated around eight percent of the country's GDP. (ANSA-AFP).