Deep down inside, you already know this: There ain’t no such thing as a free lunch, financially or otherwise.

Yes, of course, you understand that. You have heard it over and over your whole life.

If you want anything — especially something lots of other people want, too, like money — there is a simple formula that few really want to hear about. It’s no secret. In fact, it’s fairly obvious. All you need to do is work your tail off; be smarter or at least more insightful than your competition; treat every task as an opportunity to enhance your reputation; exercise good judgment; have great patience; be attentive to what matters and what doesn’t; develop social skills; learn what motivates people; avoid getting sidetracked by distractions and nonsense; continue to learn; have valuable, marketable skills; and occasionally, get lucky. Just apply some combination of the above for a few decades, becoming more efficient and productive and luckier as time goes on.

That’s not the only way to become rich. You could invent the next killer app or iPhone or cold fusion or what have you. But it is how most of the wealthy people in this country got that way.

The concept of “no free lunch” was popularized by two disparate characters: One was sci-fi writer Robert Heinlein, who offered it up in his Hugo award-winning 1966 book, “The Moon Is a Harsh Mistress.” The other was economist Milton Friedman, who actually wrote a book called, “There’s No Such Thing as a Free Lunch.”

And yet . . . so many of you find yourself drawn into all manner of get-rich-quick schemes that, truth be told, objectively speaking, can only be described as lottery tickets.

As a matter of fact, last year, Americans spent more than $70 billion on state-run lotteries. To put that into context, that’s more money than Americans spent on sports tickets, books, video games, movie tickets and music plus all of the apps, games and programs bought from Apple’s iTunes App Store — combined. That is a whole lot of money, poorly spent.

The obvious truth is that people who buy a lottery ticket want the free lunch. They want riches and financial security and oodles of discretionary income — and with very little effort. What they do have, to paraphrase New York State’s lottery logo, is “a dollar and a dream.”

Sorry, folks, but that’s not going to get it done.

It is worth noting that many lottery winners die broke and dejected. My own pet theory is that you appreciate anything you must earn through the sweat of your brow. Wealthy parents have figured out that leaving millions to their kids creates a ne’er-do-well generation, destined to die of drug overdoses or in fiery Ferrari crashes. Look no further than the insights of Warren Buffett, who long ago told his kids not to expect his billions.

Speaking of which: Stock brokers pitch the next hot stock pick — “I have it on good authority that Warren Buffett is about to take this company out!” — in order to push the free lunch hot button. (They do that because, let’s be honest, if you knew what company Berkshire Hathaway was buying next, you would immediately jump on the phone to start cold calling random strangers to share that information with. Because, you know, THAT’S what you do with that information.)

Fantasy sports leagues are the latest nonsense dangling the free lunch. They are ubiquitous on television or online. The 2006 Unlawful Internet Gaming Enforcement Act did away with online games of chance, but created an exemption for fantasy sports.

You may have noticed a tsunami of advertising for these “games of skill” with daily, rather than full season, payoffs. Anyone willing to spend that much on advertising must have the odds tilted incredibly in favor of the house. A study from the Sports Business Journal showed just how lopsided those odds are: More than 90 percent of winnings go to roughly 1 percent of players. Another analysis conducted for Bloomberg News found that the top 10 players won, on average, 873 times daily. The remaining field of about 20,000 players tracked by Rotogrinders won, on average, a mere 13 times per day.

Here is something even more amazing: A reader informs me that “the most common question Main Street Joes ask NFL football players whom they meet is who they should have on their fantasy team.” Imagine meeting a lifelong sports hero, and instead of asking a question of actual value, the moment is wasted on fantasy football.

I am not suggesting that becoming rich should not be your goal; indeed, pursuing financial security is a much more realistic and useful objective than chasing money for its own sake. However, the very human tendency to pursue a freebie often ends up costing people more than if they went the more arduous route. Of so many free lunches, this is the hard truth:

●You are not going to win the lottery.

●Hot stock tips are worthless (the only exceptions are those especially costly tips that will get you sent to federal prison).

●You are not going to buy an iPad from one of those deal sites for $3.

●No, you are not likely to buy in early to the next Apple or Netflix, and if you do, you are unlikely to hold it long enough.

●No, you are not going to make $10,000 gambling at fantasy sports.

●You (or your kid) are not going to be the next Michael Jordan or Adele.

●The odds are radically against you finding the mutual fund manager or stock broker who is going to make you fabulously rich.

●Indeed, the odds are against you stock picking, market timing or investing in a venture fund, private equity fund or hedge fund that, over the long haul, is going to outperform a simple index fund.

I spoke at a conference in Las Vegas not too long ago, at the Bellagio, where Picassos and Monets and Warhols and other priceless works of art hang in the lobby. I overheard a tourist looking at a painting remark to his wife, “Let’s go to the casino and win us one of them Monets.”

No, good sir, the reason the hotel has incredible art is because people like you pay for it via that casino. The way you get a Picasso is not by gambling your good money in Vegas, but rather by being the house where the suckers come to leave their money. There’s one born every minute, as P.T. Barnum was rumored to have mused.

Whether it’s the lotto or the stock broker or the fantasy sports leagues or Las Vegas, someone is always ready to take advantage of your desire for a free lunch. The sooner you start picking up the tab for your own meals, the better off you will be.

Ritholtz is chief executive of Ritholtz Wealth Management. He is the author of “Bailout Nation” and runs a finance blog, The Big Picture. On Twitter: @Ritholtz.