what is best to work before or after high school?

Answer 1

close by your home/neighborhood.
something you enjoy.
somewhere that your friends also work.
consider how well it pays.

Answer 2

For quick money, ups or fed-ex. For a better carreer starter that will be harder work and more time spent working, then apply for an entry level position at a big company. Like an insurance company or banking company are usually really good.