You may see no blood at all. Most women like this when they understand it is normal. Taking the pill may cause headaches, depression, anxiety, fatigue, mood changes, or decreased enjoyment of sex in some women. A backup contraceptive is required for 2 weeks if you have any question about how many pills you have missed and whether a backup is necessary. Serious complications like blood clots may occur but are very rare.
Pills can be quite expensive and require a prescription.
Pills may promote growth of breast cancer but probably do not cause breast cancer. After stopping pills, you may not get your period for 1-3 months, although this situation is rare. In the United States you need a prescription. You can get pills from your doctor, nurse practitioner, nurse midwife, health department, or family planning clinic. Not all clinicians know about this.