Regional Rail runs a little on the expensive side. Round trip from Philly back to the suburbs is $17.50. I take that to get to work sometimes. The bus, subway, and trolley are extremely affordable for what they are.

Over 1/4 of the residents in Philadelphia live at or below the poverty line so services need to reasonably priced. Some data from Pew: https://www.pew.org/en/research-and-analysis/reports/2019/07...

Can't find it right now, but I also remember a study that compared funding for other major metro transit agencies, and SEPTA ranked very highly for offering as many transit options for the amount of riders they handle given their relatively anemic budget (compared to NYC or Chicago).