ENIAC cost, in 2017 dollars, $6,300,000 to design and build. It was one of the first general-purpose computers ever built; it's purpose was to calculate trajectory tables for the Army, trajectories that been calculated by humans before ENIAC was put to work. One ENIAC hour replaced 2499 human hours of work, so this whole business of computers replacing people started some time ago—in 1946, in fact.
According to WikiPedia…
"By the end of its operation in 1956, ENIAC contained 20,000 vacuum tubes, 7200 crystal diodes, 1500 relays, 70,000 resistors, 10,000 capacitors and approximately 5,000,000 hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 2.4 m × 0.9 m × 30 m (8 ft × 3 ft × 98 ft) in size, occupied 167 m2 (1,800 sq ft) and consumed 150 kW of electricity. This power requirement led to the rumor that whenever the computer was switched on, lights in Philadelphia dimmed."
A lot bigger—and a lot less powerful—than the one you carry around in your jeans (unless you're into wearing those baggy jeans, in which case you're on your own).
You might still be able to pick one up at a flea market somewhere, who knows.