“Cheers for That” Is a Casual Thank You

In everyday Australian English, “Cheers for that” often means “Thanks for doing that”. It is more relaxed than “Thank you very much”. If someone brings you the keys, sends the information or swaps a shift, you can say, “Cheers for that.”

Here, “for that” points to the specific help that has just occurred; it is not a toast. A plain “Thanks” is equally natural. “Cheers for that” adds a casual acknowledgement that the action was useful, which suits colleagues, neighbours and people you know, but not every formal expression of gratitude.

Listen to the tone as well. If “cheers” is stressed or drawn out after someone has caused a problem, the same words may become sarcastic. The vocabulary stays fixed; the relationship and delivery change the meaning.

https://dictionary.cambridge.org/dictionary/english/cheers