MIAMI -- Marlins owners and politicians believe a new, 38,000-seat retractable domed stadium will cost taxpayers and the team $325 million.

That's before land acquisition costs in downtown Miami; costs that will add between $75 million and to $100 million to the final price tag.

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County commissioners are set to vote on the deal Nov. 4. The ballpark would open in 2007.

The stadium previously planned by former team owner John Henry and local government officials was skyrocketing towards $500 million when it was scuttled. That deal would have involved renaming the team the Miami Marlins.

Currently, there are seven retractable, domed stadiums in Major League Baseball.

Milwaukee's, which opened two years ago at a cost of $400 million,

Houston's, where play began in 2000.and which cost $250 million not including land,

Seattle's, which opened in 1999 after $100 million in cost overruns that led to bitter lawsuits and put the final price tag at $525 million,

Phoenix's, which opened in 1998 and cost $319 million.

The New York Mets hope to build a new retractable dome park (drawing shown at right); estimated cost: $600 million.

So what makes anyone think a $325 million stadium in Miami is realistic?

"To be blunt, it doesn't matter it it's a realistic figure because if they don't build it for $325, it's not going to cost us the difference," said Miami-Dade Mayor Alex Penelas on Wednesday.

Besides, Penelas said, the county has to build the stadium to keep the World Series champions in Miami. Last year, Penelas previously opposed building a stadium using public funds -- althought he says he always favored a new ballpark for the team. But the Marlins' World Series victory seems to have sparked a change of heart.

"The alternative is the team packing its bags and going someplace else," Penelas said on Wednesday, the day after the county and Marlins owners announced a deal to cover most of the new stadium's cost with a combination of taxes and about $137 million from the team. "Then you'd be asking me the opposite question: why wasn't the county a partner to the deal that would have kept Major League Baseball here?"

The Marlins will pay any overruns if the cost accelerates over $325 million, which experts say it almost certainly will. Taxpayers fear they'll get stuck with millions in hidden costs, even after the $73 million already pledged in hotel and sports facilities taxes.

And the Marlins and the county have yet to spell out where the remaining $115 million in the proposed budget will come from.

Even with the World Series trophy in Marlins hands, and despite the excitement the championship has brought to a town not known for its love of baseball, Miamians seem wary of shelling out more money to bring a baseball-only stadium to Miami.

"Our constituents are calling us screaming really loud, and when they learn the part the county is bringing to the table is not a tax increase ... (and that) it is not a question of another increase in taxes, they are confident," said Miami-Dade County Commissioner Rebecca Sosa.

In a telephone interview Wednesday, baseball economist Andrew Zimbalist was skeptical about the cost. "I will eat my hat if they can build a downtown, retractable dome stadium for $325 million," he told NBC 6 senior correspondent Ike Seamans. "This is a typical ploy of owners and politicians who start with a low figure to win approval. Later the costs always escalate, including public infrastructure costs like parking lots and improved streets."

Penelas agreed with the assessment but said the deal reached between the county and the team covers that issue. "I think he is right on point," he said. "We're in the deal for $325 million. The team guarantees all overruns."

The deadline for a stadium deal is March 15. Between now and then, the $115 million budget gap must be found from other governments including the state, which has been lukewarm to the idea in the past. Other possible sources include private corporations and individuals, who so far have shown little interest in financing stadium or arena investments in the past.

If the stadium ever gets built, local government will have to pay for infrastructure improvements like parking lots and streets. That reality has most experts agreeing that the deal has a long way to go.

Reporting by NBC 6 Senior Correspondent Ike Seamans