Tom Cruise hasn’t been spotted yet in Massachusetts, but fans and some state officials are breathing a sigh of relief that preparations are finally under way for filming of the star’s latest big budget spy thriller here.

Back in June, you’ll remember, things were a bit iffy. Gov. Deval Patrick signed into law a budget measure that would have capped at $2 million the amount of a star’s salary that would be eligible for the state’s 25 percent tax credit. But when producers of the Cruise movie, currently dubbed Wichita and costarring Cameron Diaz, let it be known that the change in the law might prompt them to take their film elsewhere, the governor and the Legislature quickly reversed course and signed into law another provision doing away with the cap.

Now film crews are busy getting ready for director James Mangold (Walk the Line) to yell “Action!” At the largely vacant Worcester Regional Airport, crews plan to spend about three weeks getting ready for three days of shooting that will yield the movie’s opening scene. The Boston Globe has been saying the Cruise film will be the biggest movie ever filmed in Massachusetts, while the Worcester Telegram & Gazette speculates that the budget for the film could hit a whopping $130 million.

That’s a lot of money in a down economy. It far surpasses what Wheel of Fortune is spending filming 15 shows this week at the Boston Convention & Exhibition Center. A Wheel of Fortune publicist says the show will bring $1 million into the region and that Vanna White will wear Boston-based fashions while she’s here. But then Wheel of Fortune, as a game show, doesn’t qualify for the state’s film tax credit and won’t cost taxpayers anything. 

By contrast, virtually every cent 20th-Century Fox spends in Massachusetts on the Cruise-Diaz film will qualify for the state’s 25 percent film tax credit. The film will undoubtedly give a boost to the local economy, but it will also be costly for taxpayers. 

Let’s say the studio pays Cruise $20 million for acting in the film, a reasonable amount given the actor’s clout and the movie’s budget. The state will then give the studio tax credits worth 25 percent of that amount, or $5 million. The studio will turn around and sell the tax credits at a slight discount to a bank or insurance company that will use them to reduce its state tax bill by $5 million.

Under the star salary cap proposed and quickly scrapped by Patrick in June, the studio would have qualified for only $500,000 in tax credits in connection with Cruise’s salary, or 25 percent of the $2 million cap. The Patrick administration estimated its star salary cap would have saved the state $20 million this year.

A Revenue Department report on the film tax credit in July said the state had issued $167 million in film tax credits over the last three years, inducing movie and TV producers to spend a total of $676 million here. Wages accounted for $429 million of the spending, with 18 percent of the money going to residents of Massachusetts and 82 percent going to nonresidents. The report said $177 million in wages went to 37 actors, directors, and producers from out of state.