In those days people who were not very well off would get a travel agency to put them in touch with other people who had cars and were going in the same direction, so that they could share the expenses.
スラッシュは文頭の副詞句の後、長い主語の後、接続詞・関係代名詞の前、カンマの
後に入れます。
In those days/ people who were not very well off/ would get a travel agency to put them in touch with other people/ who had cars/ and were going in the same direction,/ so that they could share the expenses.