If you go to the shops and buy something, you have bought it.
You have only brought something if you intended to bring something with you, and subsequently did so.
So: "I went to the shops and brought some sausages for tea" is wrong. You BOUGHT the sausages. "I went to the shops and brought my children home with me" is correct. (assuming, of course, that you bumped into your kids at the shop).
Thank you.
Apologies to anyone using said incorrect word tonight.