In production, a mold is the core tooling behind injection molding, blow molding, extrusion, die casting, forging, smelting, and stamping. Its precision and service life directly determine part-to-part consistency and the cost of volume production. From a quoting standpoint, that means the mold type has to match the process and the run length before you can talk about price. A short-run prototype tool and a high-cavity production tool are different animals, and mixing them up is one of the most common reasons quotes come back wrong.
Material selection follows the same logic. For high-volume injection work, hardened tool steels such as H13 or S136 are common where abrasion and heat are factors, while pre-hardened grades like P20 suit lower-volume runs and cut machining time. Die casting dies face thermal fatigue, so hot-work steels with good toughness are the norm, and stamping tools are usually built around the sheet thickness and expected hit count. Cavity count, gating, cooling layout, and ejection all feed into the same decision, because a cheap steel that fails at 50,000 shots is not cheap at all.
Practically, get the process, annual volume, part tolerance, and surface requirement pinned down before the tool design starts. That single step prevents most of the rework and cost overruns I see on the shop floor. For more mold sourcing information, visit MoldSo at www.moldso.com.