The price of span fabrics (spandex blends) is primarily driven by the spandex percentage (typically 3% to 20%) and the base fiber (cotton, polyester, or nylon). Higher spandex content generally increases the elastic recovery rate and cost. You must verify the fabric weight (GSM - Grams per Square Meter); a higher GSM usually indicates a denser, more durable knit which commands a premium price. Additionally, ensure the fabric meets OEKO-TEX Standard 100 for chemical safety, especially if intended for apparel.