It was very rare. In Montgomery (which OP specifically asks about), the passengers mentioned above are the only other passengers arrested before Parks, according to History.com, this NPR story, and every other source I can find.
This is further corroborated by a flyer circulated by Montgomery's Women's Political Council after Parks' arrest. According to the WPC (who were in a position to know) Parks was the second woman in Montgomery other than Colvin to be arrested for this:
Another woman has been arrested and thrown in jail because she refused
to get up out of her seat on the bus for a white person to sit down.
It is the second time since the Claudette Colvin case that a Negro
woman has been arrested for the same thing. This has to be stopped.
However, outside of Montgomery there were protestors arrested for not giving up their seats going back to at least Irene Morgan in 1944 in Virginia. Bayard Rustin and 15 others were arrested in the 1947 "Journey of Reconciliation." Sarah Keys was arrested in North Carolina in 1952.
I can't find any arrests before Morgan. Many websites (for example this one) explicitly call her the first. There may have been scattered, unheralded incidents across the South, but Morgan was the first to be arrested in a knowing effort to protest segregation.