At 30th Street Station in Philadelphia, the rates can be from $20-$35 per each 24-hour period.....I am somewhat doubtful about security there.....the underground lot is dark and not a safe place, IMHO. I would Google your city and station to see if you can obtain more specific information. I am sure some stations are quite reasonable; 30th Street is in the city and parking is at a premium, thus expensive.