Unless you have around $400 for the Midwest Theological Forum Six-Volume edition (Seriously?! How does that price encourage anyone to pray the Breviary?) then this wonderful jewel of the Church is impossible to find at a reasonable price.
Second hand copies are like gold dust, and it’s out of print at the Vatican printers, Paxbook. Anyhow they also charge well above what I’d describe as a reasonable cost for a very simple book.
I’m aware of an online source, but some of us like real books!