jojofuny 10pcs Kumihimo Disk Bulk for Beginners, Japanese Braiding Disc Tool with 32 Slots - Friendship Bracelet Weaving Supplies for DIY Jewelry Making & Creative Crafts

If you're just looking to try it, you can straight up use cardboard with slits cut and embroidery thread! If you're looking to make smaller sizes there's also these foam discs that people use for like bracelet sized stuff that you can likely find: https://a.co/d/06u6VarT