Get mad at someone

[Namsteven]

- My girlfriend usually does the shopping when she has free time or when she's angry at someone / or when she gets mad at someone.

- Is this sentences grammatical?

Thanks very much to friends!

NamSteven

[Conchita]

'To be/get mad at/with someone' is, indeed, another way of saying 'to be/get angry at/with someone'.

As to the phrase 'does the shopping', perhaps you meant 'goes shopping', which would fit better in that context. The former is often no more than a household chore and is definitely not always a pleasant and soothing activity, which is what the angry person in your sentence seems to need. Going shopping can also be an obligation for some people, but it suggests more of a leizure activity.