I read about the Nippori textile district in a magazine earlier today, I could not wait to go to the place.
How to get there: Take the JR line to Nippori station and get out of the south exit. Afterwards take a right towards the Gasto ( ガスト）Italian fast food restaurant and go down the bridge. Head straight and you will see signs that say (Textile street) all around the corners.
The textile street is about a 1 kilometer long street filled with all kinds of discounted fabric and textiles. They even sell different pre made patterns for making your own things and rolls of all kinds of straps, garters, spools of thread and all kinds of fabric mostly made in Japan and some imported from the US and Korea.