Price is built from the garment, not from a rate card. Four things set it: the materials your design calls for, the construction complexity, the number of units per style, and the finishing your brand requires. A fine-gauge cashmere sweater and a jersey knit tee move through different mills, different machines, and different amounts of hand-work, so they cost differently at identical volume.
You get an estimate before sampling begins, once we have seen your reference images and target categories. It is a real working range, informed by a decade of production data, and it is enough to decide whether to proceed. The firm quote comes after the sample is finished, because that is the point where the material, the construction, and the labour are known rather than projected. You approve a number against a garment you have held.