While Library Genesis is a controversial site, you can find legal used physical copies on AbeBooks, eBay, or Alibris. Set an alert. Sometimes a used copy costs as little as $10.

While Frawley uses Placidus for natal work, he asserts that Regiomontanus is "well suited to horary" because it is observer-based and brings the division of the heavens right down to Earth.

The Horary Textbook is suitable for a wide range of readers:

An invaluable traditional tool that shows how planets "feel" about one another, indicating motives, desires, and hidden agendas between the people involved in the question.