That is the genius of Opus Dei: lay men and lay women in every walk of life spending themselves for the service of God and neighbor in and through their professional work; and, yes, making money! putting money at the service of God.
Saint Josemaría's charism was to read the signs of the times. He saw that secular humanism had sacked, raided, plundered and shut down the monasteries. So he took the monastery to the street, to the university, to the bar, to the theater, to Wall Street, to the internet, to any profitable venture: forming contemplatives in the world in selfless service, in holiness, like Christ Himself, and under the protection of the Mother of God, faithful sons of the Church.
Saints are to be men and women like all other men and women, indistinguishable from them, and totally dedicated to God in Jesus Christ, in the Catholic faith, in every activity and using all the means which men and women use today for themselves, putting all of them at the service of God.
"The love of Our Mother will be the breath that kindles into a living flame the embers of virtue that are hidden under the ashes of your indifference."
Josemaría Escrivá, The Way, 492.