The Fashion /Garment district is around 7th Avenue at 38th Street,
near the Port Authority Bus Terminal. There are dozens of stores selling notions, fabrics, etc. Some are very specialized and some have a hodge podge of rolled cloth. Of course they cater to the designers and manufacturers, but also to the many students, from FIT (Fashion Institute) and Parsons. There are stores that specialize in costume fabrics too. One whole store of glittery spandex! A lot of fun.