The $25,000 Slate truck is proudly bare-bones. I think these add-ons are worth the extra money.

The Slate truck doesn’t have a typical key.

Unlike today’s cars — which pack proximity sensors inside a little plastic box that runs tech that allows drivers to start the engine via a push-start button — the Slate has a simple solution.

Drivers put a square key into a square slot.

There is no theatrical lighting sequence, symphony-like entrance music, or enormous touchscreen springing to life.

They’re controlled by manual hand cranks.

In my test, it took six or seven spins before the glass disappeared into the door panel.

The deliberately plain interior captures Slate’s entire pitch: Modern cars are too complicated, too expensive, and too eager to make every grocery trip feel like a Silicon Valley hype cycle.

Slate’s $24,950 electric truck (a little over $26,000, after delivery fees) starts with the basics.

Buyers can then use the company’s accessory marketplace to add back the features they care about, including speakers, upgraded upholstery, colorful body wraps, storage accessories, and towing equipment.

It is a very different way to make money after selling a car.

While other automakers increasingly rely on software subscriptions and features delivered through updates, Slate wants customers to buy physical upgrades.

I drove a prototype on Tuesday and came away pleasantly surprised.

The inexpensive truck was roomy, balanced, and genuinely fun to drive.

But the experience also showed me which modern conveniences I would miss.

These are the add-ons I’d buy to make the bare-bones Slate truck livable — plus the options I’d choose if money were no object.

I found five add-ons on Slate’s marketplace that I’d need.

The base Slate is a two-seat pickup, which could be perfect for a small business hauling products around town.

It would be considerably less useful for my life, unless I suddenly decided to stop driving my friends anywhere.

So my first upgrade would be Slate’s squareback SUV kit.

It adds a second-row bench, increases capacity from two people to five, and raises the price from $24,950 to $29,950.

My friends would be mad if that car were silent.

I spend too much time in cars listening to podcasts and Beyoncé to rely on the natural symphonies of the roadway, so I would add Slate’s $250 integrated speaker system.

Buyers committed to the stripped-down lifestyle can instead choose a universal speaker mount, though Slate has not yet announced its price.

I would also spend $100 on a locking tailgate.

Leaving the contents of the bed available to anyone walking past feels a little too bare-bones, even for Slate.

Finally, I bike enough that I would need a rear-mounted carrier and a tow hitch to hold it.

That brings my supposedly bare-bones Slate to about $31,000 before taxes and destination fees.

At that price, it starts bumping into vehicles like the base Ford Maverick and Nissan Leaf — both of which arrive with power windows, infotainment screens, and fewer decisions to make before leaving the dealership.

OK, but what if I decided to splash out?

My dream Slate would include a bevy of wildly unnecessary (but fun!) upgrades.

I would start with a blue body wrap, a white roof, matching wheel covers, and yellow accents.

Naturally, the yellow would continue inside.

And because I would also want to project outdoorsy ruggedness, I would add a rear-mounted spare tire, an upgraded bumper, fender flares, running boards, and a roof rack that I absolutely do not know how to use.

By the time I finished, my dream Slate had 28 accessories, including five that Slate has not priced yet.

The running total reached $34,949 before those final bits and bobs.

That excess is part of Slate’s appeal.

Automakers have spent years filling parking lots with crossover SUVs that increasingly blur together.

It can be difficult to distinguish a Toyota RAV4 from a Honda CR-V or Mazda CX-5 waiting in the school pickup line.

The era of the affordable personality car — think the Volkswagen Beetle or Chrysler PT Cruiser — has largely faded.

Slate gives buyers an unusual amount of freedom to make the truck look like their own, right down to a new partnership with Crayola.

Whether that is enough to create a mass-market hit remains to be seen.

But after years of increasingly interchangeable cars, it is at least fun to build one with a little imagination.