A blockbuster tax cut deal, with a 10-year cost of $889 billion and counting, is deep into negotiations on Capitol Hill, proving that Congress doesn’t care about the deficit as long as the right groups get the giveaways.

Virtually every year, Congress packages a series of over 50 tax breaks — a mix of gifts to businesses, commuters, homeowners, Puerto Rican rum manufacturers, thoroughbred horse owners, etc. — and extends them for a short period.

For lobbyists, what is known in Washington as the “tax extenders” bill is like Christmas and a birthday wrapped into one. A 2013 report from Americans for Tax Fairness and Public Campaign found that 373 businesses and trade groups hired nearly 1,400 lobbyists to push for tax extenders over a three-year period.

A House rule has made the bill even more enticing than ever. That’s because new federal spending must be “offset” by corresponding cuts or revenue raisers — but new tax cuts don’t.

That means lawmakers can blow holes in the budget without worrying about self-imposed rules. Tax extenders are the biggest freebie of the year. By comparison, Congress just this week had to scrape and claw to find enough money to fund highway spending.

Here, the challenge is not finding the money, it’s making sure there are enough goodies in the bill that gratify enough members of Congress that it can pass.

The details are fluid and still under negotiation, and the whole thing could still fall apart. But the final bill could cost as much as $889 billion over 10 years, with over 70 percent of that going to business tax breaks.

Even by Washington standards, that’s real money. For context, the highly controversial 2009 stimulus package, meant to dig America out of the deepest recession in nearly a century, cost $787 billion.

The bill would extend most of the traditional 50-odd tax breaks for a year, at a 10-year cost of around $45 billion. But it would also make six corporate tax breaks permanent, costing a whopping $667 billion.

Those include a failed stimulus measure called bonus depreciation, which allows the immediate deduction of any business equipment expenses, rather than a depreciated tax benefit over time. This was supposed to facilitate business spending during the Great Recession, but a 2013 Congressional Research Service report labeled it “not very effective.” Making it permanent allows companies like utilities, which spend heavily to build out power grids, to book large up-front tax breaks on equipment. This costs $281 billion over the 10-year budget window.

Two other measures, the Active Financing Exception (AFE) and the “look-through” rule, let corporations benefit from foreign tax havens. AFE (costing $78 billion over 10 years) enables financial institutions to defer taxes on income they claim to have earned outside the United States; all sorts of accounting tricks can make it appear like dividends, interest and other income were generated offshore. “Look-through” ($22 billion over 10 years) allows multinational corporations to move profits to tax-haven shell companies without having to pay U.S. taxes, while reducing their tax rate on real earnings.

Other proposed permanent corporate tax breaks have bipartisan support, like the research and development tax credit ($182 billion). But just giving a bunch of corporations free money won’t lead to the broad bipartisan vote necessary to force President Obama’s signature. So other perks have been added to the tax extenders bill.

The bill might also delay a tax on medical devices for two years ($5 billion), an Obamacare funding source that Democrats in states with lots of medical device companies — even stalwart liberals like Elizabeth Warren and Al Franken — oppose.

A permanent “Zadroga Act” to compensate 9/11 victims and volunteer emergency personnel (roughly $7 billion) could also be thrown in; it’s a high priority for Democrats in New York and New Jersey.

The biggest non-corporate measure would extend the Earned Income Tax Credit and Child Tax Credit, key anti-poverty tax breaks for the working poor whose expanded benefits would otherwise expire in 2017. That adds another $150 billion in cost.

The main piece that could buy Democratic support, because of the importance to labor unions, is a two-year delay of the “Cadillac tax” on high-cost insurance plans ($15 billion), set to begin in 2018. Unions believe this tax penalizes insurance that they negotiated for in labor agreements, and they question the prevailing wisdom that taxing good insurance plans will curtail health care cost growth or increase wages.

Other ideas are being considered, like extensions of tax credits for wind and solar energy, deduction of state sales taxes (which benefits wealthy earners in high-tax states like New York and California), and an adjustment for inflation to the American Opportunity Tax Credit, which gives breaks for college expenses.

But the bulk of the $889 billion price tag (for now) directly supports corporations, with scraps going to workers, students and the sick. And even the worker benefits come with strings attached: House Speaker Paul Ryan reportedly wants to erect hurdles for families trying to claim the Child Tax Credit that would limit its legal use for immigrant families. Corporations will not have to jump through any similar hoops.

The deal would also complicate future tax reform efforts, taking a number of tax breaks off the table.

The bill is being negotiated on a bipartisan basis, which accounts for all the add-ons to try and get various constituencies aboard. But Democrats and their allies will have to choose whether getting something they want, like expanded family tax credits or a Cadillac tax delay, overrides the much bigger, more egregious giveaways to corporate America.

While some fiscal conservative groups have grumbled about the cost, Republicans in Congress are proving they believe in the famous dictum uttered by Dick Cheney: “Reagan proved that deficits don’t matter.” The GOP’s lack of concern for deficits — as long as donors and friends get the spoils — has a long history.