Short and sweet:
* The market was bustling with activity.
* The city streets were bustling with life.
More descriptive:
* The bustling cafe was filled with the chatter of excited patrons.
* The bustling airport terminal was a hive of activity, with travelers rushing to their gates.
* The bustling marketplace was a sensory overload, with vibrant colors, exotic smells, and the cries of vendors.
Figurative:
* The city's heart beat with a bustling energy.
* The bustling street felt like a living organism, pulsing with life.
Using synonyms:
* The vibrant city was teeming with people.
* The lively street market was abuzz with shoppers.
The best sentence for you will depend on the context and the specific feeling you want to convey.