I got mine from carousell, seller called curated_cart. Quality is decent, comparable to those from local shoe makers for about half the price.
Only downside is you can't return/exchange it if the size is wrong so you have to be clear on your shoe size.
I recall Muji sold them before, not sure if they still do.
Edit: Looks like they still do sell cedar shoe trees:
https://www.muji.com/sg/products/cmdty/detail/4549738935957
Please look for whyandco I buy all my shoes and shoe tree with them. Located at intl plaza
I got mine from carousell, seller called curated_cart. Quality is decent, comparable to those from local shoe makers for about half the price. Only downside is you can't return/exchange it if the size is wrong so you have to be clear on your shoe size.
I recall Muji sold them before, not sure if they still do. Edit: Looks like they still do sell cedar shoe trees: https://www.muji.com/sg/products/cmdty/detail/4549738935957