Look at the edge
An ordinary key has its cuts along the edge of the blade — a row of peaks and valleys you can feel with a fingernail. A laser-cut key has a smooth edge and a winding channel milled into the flat face, usually on both sides.
They are thicker and stiffer than a standard key, and because both faces are cut identically they go into the ignition either way up.
Why they exist
The milled channel is harder to reproduce with hand tools and harder to pick, and the blanks are less widely distributed. It raises the effort involved in copying one without permission.
That same property is why they need shop equipment rather than a kiosk cutter.
What they cost
More than a standard key, for three compounding reasons: a thicker blank, a milling operation rather than a cutting one, and an embedded transponder in nearly every case.
The kiosk quotes a starting price and confirms the exact figure once it has identified the blade — before payment, not after.