Where to buy figures

So I recently started seriously collecting manga and figures, and I’ve mostly gotten my figures from Cons or Expos and I’m looking to buy more online, and I was wondering how proxys worked and different sites I can use that won’t have me paying hundreds of dollars of tariffs after the packages are shipped or even US sites that sell authentic figures. I’m perfectly ok with used figures and paying for international shipping, and i’m not planning on reselling so it’s okay if they’re out of the box too. Ive checked some websites like mercari japan but they all warn me about potential tariff costs after shipping, and Im just feeling very lost rn. I’m also located in Chicago so if anybody knows any good figure or manga stores please let me know thanks!