No sane person would spend the equivalent of his mortgage payment on tickets to a Broadway show. I’m not sane, however. I’m a fan.

When Ticketmaster designated me a “verified fan” last fall, granting me among the first chances to score tickets to “Harry Potter and the Cursed Child,” I felt so brimming with good fortune that I suspected someone had slipped a shot of Felix Felicis into my morning coffee.

Then I saw the price tag: The cost of taking my wife and twin 10-year-old boys to the show was an absurd $1,600. (Technically this was eight tickets at $200 apiece, since, in a stroke of financial dark wizardry, it’s a play in two parts — a matinee and an evening performance on the same Saturday in July).

While the “verified fan” program is designed to ensure tickets go to true devotees and not scalpers, I feared that in my case “verified fan” might also be an industry euphemism for “certified sucker.”

But after casting a few unforgiveable curses at my computer, I booked passage to Hogwarts the only way a muggle can: On the American Express.

“Good news: We’re going to Harry Potter,” I texted my wife. “Bad news: We’re going to end up in a potter’s field.”

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My wife, a verified Ph.D., came up with a more sensible plan: We wouldn’t tell the kids just yet, and if we couldn’t bear the cost and shame of such an extravagance, or didn’t hit the Mega Millions in the interim, we could always sell the tickets — probably for a profit. (She’s a total Ravenclaw.)

As it turns out, however, we had emptied our poor excuse of a Gringotts vault for nothing.

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Last week, I managed to buy four (only slightly worse) seats to the very same July performances for just $160 total — a tenth of what I had originally paid. And you can do the same. (I’ll explain how in a bit.)

These two ticket purchases, seven months and $1,440 apart, explain a lot about the price of fandom, the workings of today’s ticket market, and the danger of asking Nobel Prize–winning economists for financial advice. But I am getting ahead of myself.

Defense against the ‘endowment effect’

In spite of my wife’s plan, when the $1,600 charge hit our account, I felt so sick to my stomach I nearly shoved a bezoar down my throat.

What had I been thinking? How could I stomach such conspicuous consumption? Just weeks earlier I berated a good friend for spending a similarly stupid amount on Bruce Springsteen tickets, and then refusing to sell his seats when the asking price on the secondary market skyrocketed to more than quadruple what he’d paid.

It was a classic instance of what behavioral economist Richard Thaler famously dubbed “the endowment effect,” the cognitive bias that causes us to irrationally overvalue what we already have. My friend would never have paid $7,800 for the two seats, so logically it made no sense not to sell his seats at that price. I should add that he was also a “Verified Fan.”

The secondary market for “Harry Potter” tickets is strong, but perhaps not as insane as the frenzy over Bruce, or “Hamilton,” due to the need to purchase two plays in one, said Jack Slingland of ticket reseller TickPick. “We’re seeing the average price for Parts 1 and 2 listing for $1,450 — that’s down from $2,500 a few months ago.”

Despite this, months went by, and we still hadn’t listed our seats for sale. The endowment effect was working its dark arts on me, and there seemed to be no defense.

Reducio!

Then I got a tip. Even though the $68 million production of “Harry Potter” is the hottest ticket on Broadway, and most seats over the coming months were sold out to “verified fans” such as myself some time ago, a small number of ultracheap tickets remain available.

So I walked over to the Lyric Theater’s box office on West 43rd Street at 10:30 a.m., and went right up to the first ticket window (there was no line).

“Do you have any of the $20 tickets available for July 7? I need four,” I said. (You need to come prepared with specific dates).

“Sorry, we have seats for $310,” the woman told me.

But on the third date I attempted, she nodded. The total came to $160. I smiled and thanked her. This was all too easy. As I exited the box office, another customer at the adjacent window gave me a knowing look as he went through the same process of asking for “the cheap tickets.”

The Horcrux of the matter

At each performance of “Harry Potter,” 300 seats are sold for $40 a ticket, and of those 150 go for the $20 that I paid. This is in addition to the lottery the show holds every Friday at which 40 great seats are sold at $20 — though most fans probably have a better chance of the Goblet of Fire spitting out their name.

“From the start of our journey bringing ‘Harry Potter and the Cursed Child’ to the stage, Colin Callender and I have made it a priority to get tickets into the hands of all theatergoers,” the show’s producer, Sonia Friedman, explained.

As with the London production, the show has found that 60% of the audience is composed of first-time theatergoers, and of those 15% have gone on to see additional shows.

“They are taking a loss on these tickets,” said Mike Rafael, a ticketing expert who has consulted for many Broadway shows. “And what’s remarkable is the shows are all doing this willingly.” (Consider that, as the Wall Street Journal reported, Taylor Swift is taking the opposite approach.)

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Broadway productions have mixed feelings about lotteries, Rafael said. On the one hand they want to democratize theater, and they want a show to build an audience over years, if not decades. The downside: “They worry they have created a class of customer who will not buy at full price,” Rafael said.

When I told him how, even though the $20 seats were only supposed to be available online at TodayTix.com, I was able to walk up to the box office and get them, he said, “They are rewarding people doing their homework, which is fascinating.”

A Nobel laureate’s cure for my magical malady

So what was I waiting for? Why hadn’t I sold the more expensive tickets yet? My whole Harry Potter–obsessed family read the script to “Cursed Child” when it was published as a book, and we thoroughly enjoyed it, even if it read a bit like fan fiction.

The show is getting rave reviews and Tony nominations for its magical effects and staging as well as the performances, but I was not really expecting this to rank among my most life-changing theatrical experiences, such as Tom Stoppard’s “Arcadia” or Tony Kushner’s “Angels in America.”

Yes, the $1,600 seats in the mezzanine are going to be better than the $160 ones in the balcony, but will they be $1,440 better? Or was this just another flavor of Thaler’s endowment effect — had I simply grown attached to the idea of the insanely priced seats?

I asked Thaler to nudge me to do the right thing. After explaining to him my whole ridiculous tale, he replied with one line, proving that brilliant economists aren’t necessarily the best financial advisers.

“Maybe sitting close is worth 10x, no?”

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