Although not recommended for college-age women, fertility awareness involves tracking a women's menstrual cycle over time. The day of ovulation can be estimated by monitoring body temperature and cervical mucous. The idea behind this method is to only have intercourse when a woman is not fertile, at certain times during her menstrual cycle.
There are two common methods: the Standard Days Method (SDM) and the Calendar Rhythm Method. For SDM, a woman is considered fertile for days 8 through 19 (with day 1 being the first day of menstruation), and therefore she cannot have intercourse during these days. The Calendar Rhythm Method is similar but more specific to each individual woman. To help determine fertility, there are home test-kits that can help predict when a woman is ovulating. One must be careful with this method because of the varying patterns of most women's menstrual cycles. Usually these methods are employed by women trying to conceive a child.
Failure rates vary widely and is not a viable methods for most college students.
This method is mainly free, however it is recommended that one consult a doctor in order to figure out the days that they should not have intercourse. Also if a couple wishes to have the ovulation test kit, these are priced from about $20 and up and must be purchased on a monthly basis.