Hi, I actually have been cosplaying for a while
You can start by thrifting similar clothes or even buy something through Amazon or costume stores. And if you want to create your own cosplays or props, try to look for tutorials on how to sew/paint/design the specific part you need for your character.

I also advise to take a look to Etsy or similar markets, I've seen cool handmade stuff there too
2 months