Abraham and Sarah lived and were married in Haran. When Abraham was 75 years old, God commanded him to leave his home, and Sarah followed her husband to Canaan.
The first incident where Sarah figures prominently in the bible occurred when she was 65 years old and journeyed to Egypt with Abraham during a famine in Canaan. Despite her age, Sarah was beautiful, and Abraham was scared that if Pharoah knew she was his wife, Pharoah would kill him and take her. He therefore pretended Sarah was his sister, and Pharoah did take her, giving Abraham many material possessions in exchange. God then sent plagues to punish the house of Pharoah until Pharoah released her and sent Abraham on his way.
A similar incident transpired later in the bible with King Abimelech of Gerar. He also took Sarah, thinking she was Abrahams sister. God told him the truth in a dream and Abimelech returned Sarah to Abraham, along with a present of animals, slaves, gold and silver.
The first piece of information the bible gives about Sarah is that she was barren. This was significant since God promised Abraham earlier that his children would become a great nation. After ten years of living in Canaan, when Sarah still had not conceived, she gave Abraham her maid, Hagar, as a concubine. Once Hagar conceived, Hagar lowered her opinion of Sarah, and Sarah began to treat her harshly. Hagar ran away and returned only after God spoke to her, blessed her and ordered her to go back to Sarah. When Abraham was 86 years old, Hagar gave birth to Ishmael.
Until this point, Sarahs name was actually Sarai. When Abraham was 99 years old, God spoke to him and blessed him with children and land. He changed his name from Abram to Abraham and his wifes name from Sarai to Sarah. God also promised Abraham that Sarah would have a child, and that God would maintain his covenant with this child, Isaac.
Three days later, three men approached Abrahams tent. He invited them in and Sarah went to prepare food for them. She was listening from the opening of the tent, however, when one of the "men," who were really messengers from God, predicted that she would have a child. She laughed; after all, she was 90 years old and Abraham nearly 100! Yet God predicted that in one year, she would give birth. One year later, when Abraham was 100, Sarahs son, Isaac, was born.
Once Isaac and Ishmael began to grow up, Sarah asked Abraham to send Hagar and Ishmael away and not to allow Ishmael to share an inheritance with Isaac. Biblical commentators disagree as to the reason why she did not want Ishmael in her house. Some say Ishmael was worshipping other gods, others say he was teasing Isaac or bragging that, as firstborn, he would receive a double portion of the inheritance. God told Abraham to listen to Sarah and the next morning, Abraham sent Hagar and Ishmael away.
Sources: Encyclopedia Britannica. "Sarah". Volume 10, 15th Edition, 1997; Encyclopedia Judaica. "Sarah." 1978 Edition; Scriptures: Genesis. The Jewish Publication Societys translation, New York: 1985.