If you deck the halls etc., etc, think what it cost to deck them 100 years ago. This nation, which feels so poor, has somehow grown so rich.

1913 Christmas parties? No Chinese takeout. No frozen dinners, pizzas, potato chips or flavored yogurts. Processed cheese slices or packaged bologna slices — forget it. Instant oatmeal? I mean, please.

Shove buffalo mozzarella. Fie on tasties like organic deer liver ragout over radicchio on slices of alfalfa. Yesteryear’s staple was potatoes and, topping the shopping list, 37 cents a dozen eggs, which are now $4.99.

Milk — 35 cents a gallon. Now: skim, whole, fortified, lactate free, half-and-half, buttermilk, soymilk, strawberry milk, vanilla milk, goat milk, oat milk, chocolate milk, organic, almond, coconut, low-fat, 1 percent reduced fat — no saturated fat or cholesterol — and not hand-delivered to your doorstep — $5.99 give or take a drop.

Blame Mother Nature or Father Time. Bread increased 2,439 percent; flour 1,488 percent; sugar 1,078 percent, coffee 1,874 percent; potatoes 3,918 percent. A big jump is pork chops — 1,753 percent, bacon 1,635 percent, ham 973 percent. (Hey, those pigs have become hogs.)

Per the Bureau of Labor Statistics, excluding holiday buffets Americans spend 14 percent of today’s income on food. In 1913, women didn’t vote, didn’t work, didn’t have freezers, microwaves, computers and before the atom bomb, smartphones, moon landing, color TV, iPads and reality housecretins, and before couples’ double jobs, the families were larger and average annual salary smaller at $800.

Grand Central Station opened 100 years ago. Fries were a dime, 11 pounds of pasta a nickel, a shrimp order was 19 cents. At its eateries today linguine dotted with shrimp is $17.95. Its Oyster Bar did 19-cent cheesecake. Today’s slice — $6.95. What an Adirondack Cocktail is, no idea. Long before Michael Jordan owned his Steakhouse the thing was 75 cents. Now, $14.

So, even if Santa feels it’s a world of takers and no givers, if you’re planning to give him a snack after he squeezes down the chimney — just put out a few pretzels.

One word about Santa. Not unique anymore. Wild red outfit, big boots, bearded face, carrying a bag. Dudes who are country singers dress the same way.

If this holiday you care to catch a show, know that New York’s first theater piece “The Black Crook,” was Sept. 12, 1866. A numbing 5 ¹/₂ hours. As deadly as what happened to Scorsese’s mojo since he churned out DiCaprio repeatedly posturing, snorting and effing in “The Wolf of Wall Street” for three hours — or at least for the 30 minutes some of us stayed.

And theater time was once 8:30. Curtain was pushed up because of crime. Audiences would be out too late. Restaurateurs complained this hurt business, saying: “It only helps the muggers. Now they get home earlier.”

Christmastime 100 years ago Charlie Chaplin began his $100-a-week film career at Keystone, and a newspaper’s first crossword puzzle was printed. And — not my fault — the year our 16th Amendment, the federal income tax, was ratified.

Also the year Hollywood replaced NYC as the bourgeoning movie center. First feature release was — ready? — a sex film. An expose of prostitution.

Producer, Carl Laemmle. Cost? An extraordinary extravagant exorbitant $57,000.

Next, the Keystone Studio’s comedy short “The Bangville Police” starring Mabel Normand and the Keystone Kops. Followed by ancient vaudeville sight gags in Mack Sennett’s 10-minute short. “A Noise From the Deep” was a silent and the first to throw a custard pie in Fatty Arbuckle’s face.

1913 D.W. Griffith became a big-time name and, long before James Cameron, came the first ship-sinking saga of the Titanic, “Atlantis.”

Today movie houses show mega multi million dollar extravaganzas that are second run pictures. They were on TV first.

Itching for nightlife? A century ago, with Prohibition, we’re talking honkytonks with jukeboxes. Underground saloons were illegal speakeasies.

Today you can maybe see Lindsay Lohan, Amanda Bynes, the rear end of Miley Cyrus or the front end of non-Mrs. Kanye Kardashian of the serial divorce klan all night long. Or . . . until the sun — and they — start to get up.