The Ferengi were a humanoid species native to the planet Ferenginar in the Alpha Quadrant. As a people they were widely known as traders and business men, though not entirely as honest ones. The Ferengi were governed by the Ferengi Alliance, which had its capital on the Ferengi homeworld.
The Ferengi were shorter than many other humanoid species such as humans and Vulcans. They had an orange-brown skin tone they had large wrinkled noses and small, sharp teeth. The most distinguishing feature where their large ears, which gave them better hearing then many other species. Male ears were typically larger than females. They also had a four lobed brain that made them impossible to read by many telepathic species. (TNG: "The Price")
Ferengi culture was built around the acquisition of wealth. Their guidelines for how to live were based on this and known as the Rules of Acquisition. To the Ferengi everything had a monetary value, even friendship and loyalty.
Traditionally males and females in Ferengi society were not equal. Women were barred from business life and were expected to be house bound. It was in fact illegal for a woman to make a profit. Women were expected to go around naked and even pre-chew food for the males of their household. (DS9: "Family Business") However, in 2374, that began to change when Grand Nagus Zek introduced a bill that gave women the right to wear clothing and the Ferengi government began to consider allowing females to make a profit. (DS9: "Profit and Lace")
Ferengi religion also revolved around profit. The Ferengi believed that the universe was bound together in the Great Material Continuum and that by navigating it correctly a Ferengi would have a good and profitable life. (DS9: "Treachery, Faith and the Great River")
The Ferengi prayed to the Blessed Exchequer for guidance and fortune. Upon death they believed they would find themselves before the Exchequer who would evaluated their life based on their profit made during it. If found worthy they would be allowed to bribe their way into the Divine Treasury where the wealth he had accumulated could be used to bid on his next life under the supervision of the Celestial Auctioneers. If they failed to make a suitable amount of profit they would be cast into the Vault of Eternal Destitution. (DS9: "Little Green Men", "Body Parts", "The Emperor's New Cloak")
The Ferengi were even able to earn profit through their death. They could auction off their remains to family and friends to booster their profits before meeting with the Blessed Exchequer. (DS9: "Body Parts")
The Ferengi have a history that dates back over 10,000 years. One of the most important events was the creation of the office of the Grand Nagus and the creation of the Rules of Acquisition by Gint, which would shape Ferengi culture for centuries. (DS9: "Little Green Men", "Body Parts")