Here is a scenario where the associative property could be used. Two friends went to a movie theater and bought a movie ticket, popcorn, and a drink. The first friend bought their $6 ticket online and paid for the $4 drink and $3 popcorn together at the concession stand. The other friend bought the $6 ticket and the same size drink at the counter. Later, they decided they wanted a $3 popcorn and went back later.
Here is the math problem showing each scenario as equal. The associative property is being used.