Halloween // Easy DIY Lily Munster costume?

I've been wanting to dress up as the OG spooky queen for years but I don't really want to spend $70 on an ill-fitting polyester dress. There's a secondhand store near me I've scoured but most of the dresses are stuff for prom or cocktail gowns, no gauzy dresses or skirts. Also, I have shoulder length brown hair; is it really worth buying a wig?

Any ideas? If you made a Lily costume, how did you do it? Thanks ❤️🧛‍♀️