Well, a basic covered pit trap has a cost of 1,800 gp (:eek:) and has a craft dc of 20 (:eek::eek:) if your character has craft (trapmaking) +10 then he will first need to spend 600 gp's on raw materials (:eek::eek::eek:).
By taking 10, he can succeed at the craft DC automatically, and complete...