Arizona’s Jan Brewer became the third Republican governor to accept the Medicaid expansion offered through Obamacare on Monday, accepting one of the key components of President Barack Obama’s health care overhaul plan after spending months reiterating her “unwavering” opposition to the law.

In a speech on Monday, Brewer said expanding Medicaid is the right financial decision for Arizona since the federal government will reimburse states for the cost of expanding the government health program. The decision is expected to extend health coverage to an additional 30,000 uninsured state residents.

Arizona had the second-highest poverty rate in the nation in 2010, according to 2011 estimates from the U.S. Census Bureau. About 18 percent of people in the state did not have health insurance that year.

Brewer had previously alleged implementing a state-based health insurance exchange would be incredibly expensive and burdensome during a time when many Arizonans are still struggling to meet ends meet.

“A state Exchange would be costly. Though the federal government has pledged to pay nearly all startup costs, states that form their own health exchanges are on the hook for operational expenses beginning in 2015. Those costs could total $27 million to $40 million annually for the state of Arizona, according to a recent study conducted by Mercer. Of course, these expenses would be passed along in the form of fees resulting in higher health premiums for Arizona families and small businesses,” Brewer wrote in a November letter to Gary Cohen, the director of the Office of Consumer Information and Insurance Oversight.

Brewer joins New Mexico Gov. Susana Martinez and Nevada Gov. Brain Sandoval, who were the first Republican state leaders to agree to expand Medicaid in their states. But at least eight other GOP governors, including Texas Gov. Rick Perry, Oklahoma’s Mary Fallin and Wisconsin’s Scott Walker have all said they will not participate in the Medicaid expansion, which would offer health benefits to people earning up to 133 percent of the federal poverty level –- about $14,956 in 2013.

The allegedly excessive cost of expanding Medicaid has been one of prime reasons some state leaders have refused to participate in the program. However, some lawmakers may be exaggerating its sticker price.

Republican Florida Gov. Rick Scott was recently called out by the state’s chief economist for reportedly severely overestimating the cost of the state expansion. According to a series of e-mails uncovered by Health News Florida this month, Scott was aware that the numbers he cited were incorrect after aides pointed out inconsistencies in December. However, the governor continued to publicly use those estimates for weeks afterward.