How much do customs broker's services cost to import a 40' container into the US through the Miami port?

That depends on what is in the container. If the container contains a mixed load … different products from different suppliers it could cost many thousand $

Well, it would definitely depend on different factors. So, you`d better choose a reliable broker and ask them about the procedure and costs to be on the safe side. I used to apply to this company https://clearitusa.com/ and was pretty satisfied with their services. They are many years in that business and will definitely help you safe money and nerves.