Frankly, if they rip off school districts in order to keep kids from inhaling nitrogen dioxide, that's still a better business model than most of the ones I've heard.
I think that depends on the extent to which they rip them off.
I guess you're probably right. But it seems like we're looking at a small factor (2-3) applied to the usual price of a school bus. Of course, there are also reasons it might not be a ripoff, as others brought up (lower ops costs, economy of scale). I just felt like highlighting the problems with prioritizing price over all else around the health of primary schoolchildren.