In speech it isn’t always clear whether someone says brought or bought, but I really hate seeing them written in the wrong context so here are definitions to help people get them right…

bought: to have purchased something. It is the past tense of the word buy.
They bought their car from a registered dealer

brought: to have carried or taken something/someone with you. It is the past tense of the word bring.
She brought a friend with her to the conference.

‘After you bring something you’ve brought it’ is a handy reminder of which is which as many people get confused over these two words.