PG128 of the DMG tells us that you can construct a trading post with 5000GP and 60 days of downtime.
In terms of raw materials used a guillotine should be SIGNIFICANTLY cheaper, and in terms of construction costs would not take nearly as long to build.
Counterpoint: Adult Dragons have 19d12+133 HP but a single adult Rich can be defeated with a single 2d10 ammunition.
PG128 of the DMG tells us that you can construct a trading post with 5000GP and 60 days of downtime.
In terms of raw materials used a guillotine should be SIGNIFICANTLY cheaper, and in terms of construction costs would not take nearly as long to build.