Heads up, they’re expensive because they are not mass produced. Almost all corsets made to be everyday garments are specialty items made by very small shops or individuals catering to reenactors and other niche markets.

However, if you take care of it it should last a decade or more, so if you can afford it it might be a great investment for you.

I was going to suggest Redthreaded, but it looks like they swapped to only doing patterns just this past December 😞

Here are some others but I have not purchased from them myself.

https://www.periodcorsets.com/corsets

https://www.etsy.com/shop/natalisadesigns

https://www.etsy.com/shop/AtelierSylphecorsets/

I know Atelier Sylph has an excellent reputation, their patterns are highly regarded

https://nemuro-corsets.com/collections/historical

https://theboudoirkey.com/collections/corsets-all-offers

I second wanting to know those shops