Look who’s in the final eight in the MLB playoffs — the Oakland Athletics, Miami Marlins and Tampa Bay Rays, who ranked 25th, 27th and 28th in payroll out of 30 teams this season.

Look who didn’t make the playoff field — half of the top 16 teams in payroll, including the Nationals, as well as the Philadelphia Phillies, New York Mets and Boston Red Sox, who had even higher payrolls than Washington. The Los Angeles Angels, with Anthony Rendon, didn’t make it. Even with a crazy-low 16-team playoff bar, half the “spenders” flopped.

This, or something akin to it, often happens in October. We have mystery interlopers who shouldn’t be there. Yet they are, over and over. We act like we’ve never seen it before. Of more interest to me, we seldom ask: “How is it possible to build many very good teams on a teenager’s allowance? Is there a trick?”

Spoiler alert: There is. It’s the ability to find and amass average players, perhaps a dozen of them on the roster, at dirt-cheap prices. They aren’t gaudy enough for rich teams who can “afford anybody.” But the rich often finish behind, or no better than, the poor while wasting $100 million to $150 million per year.

At this time every year, I hear that the teams with the biggest payrolls — at the top this year, per Cot’s Baseball Contracts, are the New York Yankees, Los Angeles Dodgers and Houston Astros — are an overwhelming choice to win the World Series. And I always wonder, “What sport are they watching?”

Of the past 20 World Series winners, seven were not in the top 10 in payroll. Others were 10th, 10th and eighth. The teams that have “bought titles” with payrolls in the top three since 2000 are the Red Sox (four times) and the Yankees (twice).

In baseball, it helps to be rich. But when we focus on expensive rosters, we miss a key point. MLB is the sport where a “poor” team has the best chance to build a contender and where assembling lots of average players, along with a few stars, can take you a long way.

This season, before the pandemic changed the math, the Yankees were set to pay their players $265 million — while the Rays, A’s and Marlins combined were going to pay $288 million.

If MLB has a problem, certainly a small one compared to other sports, it’s that teams in the bottom 10 in salary, even if they win tons of regular season games, seldom win it all.

MLB has one-hit wonders who won the World Series with modest payrolls, such as the 2002 Angels (14th), 2003 Marlins (20th), 2005 Chicago White Sox (13th) and 2015 Kansas City Royals (13th). But they didn’t stay on top for long. What’s remarkable is some teams overcome massive financial disadvantages for years or even decades.

Being onstage in October is nothing new for the Rays, who have won 90 or more games seven times in the past 13 years and went 40-20 in 2020. They’re the No. 1 seed in the AL. Tampa Bay has done this while averaging the fourth-lowest payroll in baseball since 2008. The Rays are 157 games over .500 in that span.

Being at the October party is old hat to the A’s, too; they’ve won from 87 to 103 games 13 times in the past 22 years and were 36-24 this season. The “Moneyball” theories of Oakland executive Billy Beane, now used throughout baseball, are still at the core of why all these “cheap” teams play like they’re rich.

These franchises often play in ugly parks and are always poverty stricken. It never stops them. Cleveland, 24th in payroll, just had another fine, contending year (35-25). In 15 years, Cleveland has won at least 90 games seven times; four years ago, it was one win from a title.

Minnesota, which won the AL Central at 36-24, has ranked 18th or lower in payroll in all but three seasons in the 21st century. Yet the Twins have made the playoffs in nine of the past 19 years.

And the Marlins are on the verge of fielding a fine young team, most of it done with strings and mirrors — or kids.

Almost all of these teams focus on the draft, international scouting and player development, and they usually let their young stars go before free agency arrives. But they sometimes dodge that bullet by offering early long-term deals to players who have barely reached the majors, such as the Rays with Brandon Lowe.

Somebody tell the Nats that this might’ve worked with Rendon, might still work with Trea Turner and could be vital over the next decade with Juan Soto and Luis García. Each is at a vastly different contract level. But the point is the same: The team trusts its judgment, takes a risk and hopes the player likes the trade-off of security vs. last possible dollar.

You assume a lot of risk by betting on projections, but you don’t have to bat 1.000 to make it work. Look what the Rays did with Lowe after he hit .233 in 129 at-bats as a rookie in 2018. A Nats “comparable” might be García. The Rays gave Lowe a six-year, $24 million deal with two team options. Now, the happy Rays are set to have Lowe, who will get some MVP votes, for eight years and $46 million — probably half, or less, of what he’s worth.

Amid the welter of modern stat tools, one idea often gets buried: The difference between a great or near-great player and an average or slightly above-average player is enormous in terms of glamour, fan appeal, all-star and even Hall of Fame consideration. But the difference — on the field, in run differential and in the standings — often just isn’t that big.

For instance, Bryce Harper is on a Reggie Jackson-like Cooperstown track. He is worth a lot more than the frequently mentioned “replacement player” who is a bench warmer or Class AAA call-up. But how much more is he worth than an average MLB player? That’s a different stat, called wins above average. In 2019, Harper was worth about 2.2 wins more than an average right fielder. For all nine years of his career, he’s worth about 2.1 wins per year more than an average player.

The Rays, A’s, Marlins, Indians, Twins, Royals and many others will never be able to afford a Harper in free agency. How can you get around it?

In 2019, the entire Rays team was 11.7 wins above average. That means that they should have won 11.7 more games than an 81-81 team — or about 93 wins. The Rays played well in one-run games and won 96.

How did they get those 11.7 extra wins above average? The Rays had 10 players whom they paid about $7 million in total. A few were good, cheap prospects. Those 10 produced 10.2 wins above average.

Who were these stalwarts? Willy Adames, Ji-Man Choi, Yandy Díaz, Austin Meadows, Tyler Glasnow, Nick Anderson, Yonny Chirinos, Oliver Drake, Emilio Pagán and Ryne Stanek. No, I don’t know many of them, either. The Rays also had several other (0.0) average guys. They helped because avoiding negative players boosts you, too.

It’s tough to win a World Series with 15 or more “average” players on your low-budget roster. But, this October, if the Rays, A’s or Marlins somehow advance, you might want to pull for them. In a way, they are the teams that are truly remarkable.