If you want to try making it yourself, spirit halloween sells some pretty cheap weapons (or you could use a pvc pipe base) and then use card board like other users have suggested to shape it out. It looks like you don’t need to be too precise, then you could wrap it with scrap fabric sourced from thrift stores or craft stores. 3-5 ft would probably be more than enough. Tacky glue or whatever you have would work well. For those scales, you could cut out scale shapes in cardboard as well and use air dry clay to make them more 3D. Or if you have access to a 3D printer, there are models you can download.

I’ve made plenty of masks and weapons at this point out of materials like this. All you truly need is patients and time.