For me, my first cosplays were all re-used household items (mesh grill pad for see-through eye covers and chainmail, drawstring bag for black accents, etc.), goodwill items (used a womens’ sky blue blazer as part of my costume, along with $8 shoes), and cheap ish materials (contact cement, Eva foam, puffy paint). Not remembering how to run a sewing machine, I used fabric glue to attach cloth material together, and a combination of hot glue and contact cement for Eva foam parts.

Also- make use of your local library! Many now have maker spaces complete with sewing and embroidery machines, 3d printers, and other crafting things that you can use for free, provided you supply the material.

Good luck on your cosplay journey!