One student was walking 4.5km to and from school before the Old Boys' Association kicked in to help him and bought him a Smartride ticket, he said.
Other parents had not sent their children to school if it was a bad weather day during winter.
"We have had parents contact the school to say 'Johnny' is away today because it's too wet for my son to walk to school. They can't afford the bus so they keep them at home so they don't get sick."
Mr Mangan said most would think it was a fundamental right "when we talk about a free education, if that is possible, and likewise free transport, but we are hitting at our most vulnerable".
Otumoetai College principal Dave Randall said the school had lost out-of-zone enrolments because parents could not afford bus fares.
"People have a right to come to school and it's taking that right away to go to your nearest school of your choice."
The school had also helped a couple of families with bus tickets.
Mother of two Andrea Crawford said the introduction of bus fares was a shock and proposed increases were ridiculous.
She could not drive her kids to school because she worked and the cost of bus tickets had ultimately come off the family's food bill.
"It's just money that has to come from nowhere so at the end of the day it comes off our food bill."
However, she was willing to make that sacrifice for her children's education.
Bay of Plenty Regional Council transport policy manager Garry Maloney said when Tauranga's free bus fares ended at the start of term two for about 3000 students, following the Ministry of Education's decision to withdraw funding, subsidises would cost ratepayers $531,000.
It realised the introduction of fares meant some people might not choose to use the school bus service, he said.
"But we are happy to be able to offer an option for many Tauranga students to use in getting to school. While there was a perception that the previous ministry service was free, it was really just funded in a different way and by charging fares we're putting a portion of the cost back on to the user, but it still needs to be an economically viable business option for us to provide the service."
If affordability was an issue the Ministry of Social Development might be able to help, he said.
Tauranga Budget Advisory Service manager Diane Bruin said children catching the bus had become a luxury for some families and another cost that needed to be budgeted for.
People were going without other things or looking at alternative ways to get children to school, she said.
A Ministry for Social Development spokesman said the ministry encouraged anyone with immediate and essential costs that they were not able to cover to get in touch with Work and Income to see what assistance they might be eligible for.
Student bus fares 2015
* Concession Smartride fare: $1.15.
* Cash fare: $1.60.
* Savings on usual fare: 20c (cash) and 29c (card).
- Source BOPRC
Transport subcommittee 2016 recommendations
* Based on current patronage, it is likely that if the subcommittee's recommendations stand, there will be a variance in the 2015/16 revenue budget for Tauranga buses of about -$213,600 (that is, revenue under-recovered by this amount).
* The recommended staff option would see council set the same child/student fare for both the BayHopper and SchoolHopper at $1.51 per Smartride trip.
* Committee will meet to consider options on Monday.
- BOPRC