Q: How is zipper sampling charged?
Sampling is normally quoted as a charge per style, covering materials, setup, machine time and inspection. The fee is often credited back, in full or in part, against the first bulk order, so it functions as a commitment deposit rather than a pure cost. Custom colors, engraved sliders and new tooling are usually quoted separately because they involve dedicated setup.
Ask what the sample fee includes: the number of pieces, the length options, color matching to a submitted standard, testing and courier. A quote that seems low may exclude the dyeing charge or the international freight, which can exceed the sample cost itself. Clarify whether the sample is made on production equipment or on a laboratory line, because the two do not always behave the same.
Keep the approved sample and its signed specification. It becomes the reference for bulk inspection and for any later dispute about shade, hand or slider feel. If the program is large, negotiate a sampling schedule with several rounds built in, since one round rarely resolves color, length and hardware at the same time.