We gave five treasure hunters €100 each and sent them off to bag bargains. In next week's series conclusion, James O'Halloran of Adam's Auctioneers will value the items and the winner will get €500 for the charity of his or her choice. Catherine Cleary's charity is Headstrong, the youth mental health charity.

Hard-nosed treasure hunters aren't swayed by coincidence and Kevin Spacey. But I have a soft spot for serendipity. So here's how it happens. It's a Sunday morning and I'm looking online for an image of an Underwood typewriter. Someone needs me to give them something on an official letterhead. I don't have one. But I do have an obsession with House of Cards. The scene where Frank Underwood pulls out an Underwood typewriter and types the most audacious letter of his life pops into my head. So I find a drawing of an Underwood typewriter and paste it on the top of my letterhead. It's hackneyed and lazy. I need a typewriter for work about as much as I need a butter churn. But it'll do.

A few hours later I’m wandering around the monthly flea market in Dublin’s Newmarket Square with a nagging suspicion that any real treasures have been bagged by early-rising hipsters.

The market is busy. There are lots of secondhand clothes, a blue canvas Swissair cabin bag, and some ferociously ugly china. And then I see my treasure. It’s a handsome black Underwood typewriter sitting on a shelf, its case open behind it like a snake-oil salesman’s travelling bag displaying wares. To my eye there’s a huge neon-bulbed arrow pointing down at it from the sky that reads “Buy me”.

The stallholder, Suzie G Walls, is selling it for €65. She thinks it's from the 1950s and she bought it in San Francisco in 1998, she says. I have a phobia about haggling. But it's fading the older I get. So I try out my line. "Is that your best price?" And we settle at €60. I am a haggler. One who settles quickly, but a haggler nonetheless.

“We already have a printer,” the five-year-old says, bewildered by this hunk of metal when I put it on the kitchen table. I slot in some paper and I’m back in a high-ceilinged room in my Dominican secondary school getting my typing speed up to 80 words a minute. That skill got me through college, one temping job at a time.

I remember how to load the paper and the surprisingly physical effort it takes to make the keys punch a proper impression on the whiteness of a page. My little finger feels too weak to match the power of my index finger, so my “a” lacks the emphasis of my “f”. I have a vague memory that we were taught to type on manual typewriters, as they were tools that were unforgiving of a woolly aim. Then we were allowed to move on to electronic ones. So I have a notion of what to do when the keys clump together and have to be eased apart to drop back faithfully into their slots.

Ghostly letters

The ribbon is spent, but ghostly letters appear from the ink left on the keys. Later, when father-and-son typewriter experts on Dorset Street rub the ribbon between their fingers, they will chuckle to each other at how dry it is. “Feel that. It’s like cardboard.” My right hand keeps automatically swiping for a non-existent carriage return on the right-hand side. On this Underwood, the carriage return is only on the left. There’s a delightful ding as the carriage gets close to the end of a line.

I’m struck by how differently people must have written using this machine. The sentences would have to have been made in their heads before they hit the paper. Instead of flowing out of a blinking cursor to be read and deleted and rearranged to run smoothly, they would have had to come out in precise order. Transferring thoughts from mind to paper was a linear, staccato business.

"How much did you pay for it?" Joe Miller in the Typewriter Shop on Dorset Street asks when I ring him up to ask about getting a new ribbon. I won't tell him over the phone, but we agree I'll bring it in to show him. "How much should I have paid for it?" I want to ask, but I'm not sure I want to hear the answer.

The internet has valued my handsome contraption at anything from €10 to more than €440. The Typewriter Shop opens between 10.30am and a 10.45am, he says. He packs up for the day at about 4.45pm. And they close at midday on Friday. The typewriter business is a quiet backwater.

“Stick it up on the table,” says Joe Miller when I arrive with my Underwood in its case, as though it’s a sick pet. The Typewriter Shop looks like a storeroom. It’s a little shop of obsolescence. “But it’s obsolete technology that people are looking for,” he says firmly.

An older man arrives from upstairs and we make our introductions. He too is called Joe Miller. He supplied the Brother EP 44s that Irish Times reporters brought to Tiananmen Square in 1989. They were "cutting-edge at the time" because they had a modem and basic word-processing ability.

Joe snr opens the case. “It’s a very nice machine,” he says. “It might need a bit of oil.” One of the spools on the ribbon is the wrong size and they’re both plastic. Originally they would have been steel.

Crossed the Atlantic

Before I get too excited, he tells me these typewriters were made in their hundreds of thousands in Bridgeport, Connecticut. This one has a pound-sign key and a stamp from an Exeter repair shop with a four-digit phone number, so it was obviously sold to be used in Britain. It crossed the Atlantic at least three times: once to be shipped from the factory to England, and then back to the US, before being bought in San Francisco and taken to Ireland.

“Long shot, but it could have been brought by a US serviceman after the war,” says Joe snr. We talk through the ideas of rare, scarce and collectible, the three categories of items, in descending order of value. They find the serial number, G1131658, which should hopefully date the machine somewhere in the 1930s.

They tell me there’s a resurgence in typewriters. Are young people getting into them? “Well, it’s more mature than younger people,” says Joe jnr.

Joe snr will make me a new ribbon with steel spools for €20. He will call me when it is ready to be fitted.

They insist on tying the case with its broken hinge up with strong orange twine before I leave, so that my Underwood Campion portable typewriter doesn’t drop out and smash on Dorset Street.

“Smell that. That’s old typewriter,” says Joe snr, taking a deep inhalation from the innards of the machine before we box it up.

I’ve already had a good sniff, I tell them, when they worry that smelling old typewriters makes them sound like crackpots.

“I’m a crackpot, too,” I say. I love the smell. It’s the smell of musty old paper, dust, ink, wonky typing and a musical ding when you are near the end of a line.