[Pontiac]

This has always been cheap and practical

But occasionally gory. Such as when the noose decapitates the condemned.

Cheap and effective would be gassing the condemned with a cheap industrial gas like Nitro oxide, nitrogen or carbon monoxide.

There would be no pain with any of those gasses.

A small air tight room with an inlet pipe and an exhaust pipe with control valves, a couple of gas bottles and the correct regulator valve, add in the appropriate alarming gas meters for the exterior of the room.

The entire system should cost less than $100K to build maybe $50k or less to design.

Any protest that the condemned would suffer pain would be without and grounding in science.

[Magnum44]

I wont argue with you. But I may bid against you.

Gallows lumber - $300
Nails - $30
Door hinge - $10
Noose rope - $50

All available at Home Depot and no special handling permits required.