Big changes are coming to the way people buy and sell houses in the United States. The National Association of Realtors settled a lawsuit last week that could up-end the way real estate agents are paid, doing away with the traditional agent’s commission of 5-6%. That’s prompting a reckoning for buyers, sellers and real estate agents. Here are six things to know.

What if you already sold a house?

As part of the settlement, the National Association of Realtors agreed to pay $418 million over the next four years. That’s in addition to $210 million that various brokerage firms had already agreed to pay. Lawyers will get a chunk of that money, but the rest will go to people who sold their homes in recent years and paid what critics argue were inflated real estate commissions. Eligibility depends on where you live, but in some parts of the country, the settlement covers people who sold homes as much as a decade ago.

“We don’t know the exact number, but we estimate it to be in the neighborhood of 40 or 50 million” people, says Benjamin Brown, co-chair of the anti-trust practice at Cohen Milstein, one of the law firms involved in the class-action case.

To find out if they’re entitled to compensation, sellers can check the lawyers’ website: www.realestatecommissionlitigation.com.

How will this change real estate commissions ?

For decades, the norm in this country has been for the person selling a home to pay both her own agent and the buyer’s agent. What’s more, the buyer’s share of that commission had to be spelled out in order to advertise the home on the big regional listing sites. Realtors insist they never fixed those commissions, but as a practical matter, the public notice worked to set a standard — often in the neighborhood of 5 or 6%, split between the seller’s agent and the buyer’s agent.

For a home priced at $400,000 — which is close to the national average — that works out to $20,000 to $24,000 in commissions — much higher than people in other countries typically pay. In Germany, commissions average 4.5%. In the UK, they’re under 2%.

Starting in July, sellers will no longer have to spell out a commission for the buyer’s agent. Advocates say that should lead to more negotiation, more competition and ultimately lower costs.

What increased negotiations mean for buyers and sellers?

There’s going to be more opportunity to shop around, and likely a wider array of services, from deluxe agents who charge a premium price to discount agents with more limited services — similar to what exists in other markets like stock brokers and travel agents.

Sellers may be able to negotiate a flat fee to market their house, not connected to the selling price. Buyers may be able to purchase a la carte services — paying less if they do their own house-hunting on the Internet and more if they want to be chauffeured around to open houses.

Many sellers may decide not to pay the buyer’s agent, leaving buyers to shoulder that cost on their own, or go without an agent altogether.

Overall expenses are expected to be significantly lower, however. Economists at the Federal Reserve Bank of Richmond estimate the changes could save homebuyers $30 billion a year, with most of those savings coming out of the pockets of real estate agents.

What does this mean for agents?

Agents are still sorting out what this might mean for their business. When fees are more negotiable, agents will have to make the case for what they’re worth. But the best agents feel like they do that already.

“Do I think that Realtors have to learn to do business in a different way? Absolutely,” says Kevin Wilson, president of the Greater Nashville Realtors. “But I also think this is a wrinkle in the landscape. Not a landmine.”

A drop in commissions might drive some agents into other lines of work, but that’s not necessarily a bad thing. The U.S. has 2.5 to 3 million real estate agents — which is far more than any other country, relative to the size of its housing market. For example, the U.S. has about six times more home sales each year than the U.K. does, but 26 times more agents.

“Do we see agents that work with buyers start to phase out of the business because they’re just not getting as many clients?” asks Jovani Ortiz, an agent on Long Island. “These are sort of the unknowns that most agents are looking at right now.”

While the commission pie is likely to shrink, it may be cut into fewer slices, so the remaining agents might end up making the same amount of money.

With home prices and mortgage rates already high, how will homebuyers pay for their own agents?

While sellers have traditionally paid buyers’ agents in the U.S. (and built that expense into the sales price of their home), many sellers may opt not to pay buyers’ agents in the future. In that case, buyers will have to pay their own agent out of pocket, on top of a down payment and other closing costs. Finding thousands of dollars to pay an agent could be a challenge, especially for first-time buyers, who typically have limited funds and also the greatest need for an agent’s guidance. First-time buyers accounted for just 26% of existing home sales in February — tying a record low.

“Many first time buyers are already at the absolute max of what they’re able to borrow,” says Vanessa Perry, a professor at George Washington University School of Business and a fellow at the Urban Institute’s Housing Policy Finance Center. “They’re not going to be able to come up with any additional cash to pay their own agent.”

Home sellers could still agree through negotiation to pay the buyer’s agent. But in a hot housing market, sellers may have little incentive to do so. Eventually, buyers may be able to fold the cost of their agent’s commission into their mortgage, stretching the payments out over the life of the loan. But that will require a change in mortgage underwriting rules. Over time, lower real estate commissions should lead to somewhat lower housing prices.

What should people who are thinking of buying or selling in the next six months do?

The settlement’s changes in commission rules take effect in July, just as many people will be shopping for homes ahead of a new school year. But it’s not clear how quickly the landscape will change. Buyers and sellers may want to talk with their agent about the costs and benefits of moving before the deadline or waiting until the new rules are in place. Remember, commissions account for $20,000 to $24,000 on a typical home. Still, that’s just one factor to consider when deciding when to buy or sell — along with interest rates, the supply of homes on the market and life circumstances like a new job or family member.