Ferengi Rules of Acquisition
The Ferengi Rules of Acquisition were conceived by the first Grand Nagus Gint millennia ago (DS9: "Body Parts"). In theory, "every Ferengi business transaction is governed by [these rules] to ensure a fair and honest deal for all parties concerned" (DS9: "The Maquis I").
There were 173 rules in the 22nd century (ENT: "Acquisition") and 285 rules by the time of TNG: "The Price" in 2366 (VOY: "False Profits"). This number remains constant for at least until 2369 (DS9: "Rules of Acquisition"). In 2370, the Ferengi government is debating an amendment to the Rules of Acquisition (TNG: "Bloodlines"). As of 2373, there exist 47 commentaries, 900 major and minor judgments, and 10000 opinions. "There's a rule for every conceivable situation" (VOY: "False Profits"). In addition, there is a concept of "the Five Stages of Acquisition: Infatuation, Justification, Appropriation, Obsession, and Resale" (VOY: "Alice").
There are at least 289 rules by 2381. It seems unlikely that the Ferengi in LOW: "Old Friends, New Planets" makes up the new rule #289 on the spot during the skirmish with Mariner's ship.
Canon Rules
1 "Once you have their money, you never give it back."
DS9: "The Nagus"
3 "Never spend more for an acquisition that you have to."
DS9: "The Maquis II"
6 "Never allow family to stand in the way of opportunity."
DS9: "The Nagus"
7 "Keep your ears open."
DS9: "In the Hands of the Prophets"
8 "Small print leads to large risk."
LOW: "Parth Ferengi's Heart Place"
9 "Opportunity plus instinct equals profit."
DS9: "The Storyteller"
10 "Greed is eternal."
DS9: "Prophet Motive"
16 "A deal is a deal... until a better one comes along."
DS9: "Melora"
17 "A contract is a contract is a contract. But only between Ferengi."
DS9: "Body Parts"
18 "A Ferengi without profit is no Ferengi at all."
DS9: "Heart of Stone"
21 "Never place friendship above profit."
DS9: "Rules of Acquisition"
22 "A wise man can hear profit in the wind."
DS9: "Rules of Acquisition"
23 "Nothing is more important than your health... except for your money."
ENT: "Acquisition"
28 "Whisper your way to success."
DS9: "Treachery, Faith, and the Great River"
31 "Never make fun of a Ferengi's mother."
DS9: "The Siege"
33 "It never hurts to suck up to the boss."
DS9: "Rules of Acquisition"
34 "War is good for business."
DS9: "Destiny"
35 "Peace is good for business."
DS9: "Destiny"
45 "Expand or die."
ENT: "Acquisition"
47 "Don't trust a man wearing a better suit than your own."
DS9: "Rivals"
48 "The bigger the smile, the sharper the knife."
DS9: "Rules of Acquisition"
57 "Good customers are as rare as latinum. Treasure them."
DS9: "Armageddon Game"
59 "Free advice is seldom cheap."
DS9: "Rules of Acquisition"
62 "The riskier the road, the greater the profit."
DS9: "Rules of Acquisition"
74 "Knowledge equals profit."
VOY: "Inside Man"
75 "Home is where the heart is, but the stars are made of latinum."
DS9: "Civil Defense"
76 "Every once in a while, declare peace. It confuses the hell out of your enemies."
DS9: "The Homecoming"
91 "Your boss is only worth what he pays you."
LOW: "Old Friends, New Worlds"
94 "Females and finances don't mix."
DS9: "Ferengi Love Songs"
95 "Expand or die."
DS9: "False Profits"
98 "Every man has his price."
DS9: "In the Pale Moonlight"
102 "Nature decays, but latinum lasts forever."
DS9: "The Jem'Hadar"
103 "Sleep can interfere with..." [incomplete quote]
DS9: "Rules of Acquisition"
109 "Dignity and an empty sack is worth the sack."
DS9: "Rivals"
111 "Treat people in your debt like family: exploit them."
DS9: "Past Tense I", "The Darkness and the Light"
112 "Never have sex with the boss's sister."
DS9: "Playing God"
139 "Wives serve, brothers inherit."
DS9: "Necessary Evil"
190 "Hear all, trust nothing."
DS9: "Call to Arms"
194 "It's always good to know about new customers before they walk in your door."
DS9: "Whispers"
203 "New customers are like razor-toothed greeworms, they can be succulent, but sometimes they bite back."
DS9: "Little Green Men"
208 "Sometimes the only thing more dangerous than the question is an answer."
DS9: "Ferengi Love Songs"
211 "Employees are the rungs on the ladder to success. Don't hesitate to step on them."
DS9: "Bar Association"
214 "Never begin a business negotiation on an empty stomach."
DS9: "The Maquis I"
217 "You can't free a fish from water."
DS9: "Past Tense I"
229 "Latinum lasts longer than lust."
DS9: "Ferengi Love Songs"
239 "Never be afraid to mislabel a product."
DS9: "Body Parts"
263 "Never allow doubt to tarnish your lust for latinum."
DS9: "Bar Association"
285 "No good deed ever goes unpunished."
DS9: "The Collaborator"
289 "Shoot first, count profits later."
LOW: "Old Friends, New Planets"
Uncertain Rules
Number unknown "Exploitation begins at home."
Number unknown "Time, like Latinum, is a highly limited commodity."
DS9: "The Bar Association"
Probably another rule "A good lie is easier to believe than the truth."
DS9: "Shattered"
Number unknown A rule that recommends to verify goods before purchasing them
DS9: "The Abandoned"
Hoax Rules by Grand Nagus Zek
1R "If they want their money back, give it to them."
DS9: "Prophet Motive"
10R "Greed is dead."
DS9: "Prophet Motive"
21R "Never place profit before friendship."
DS9: "Prophet Motive"
22R "Latinum tarnishes, but family is forever."
DS9: "Prophet Motive"
23R "Money can never replace dignity."
DS9: "Prophet Motive"
285R "A good deed is its own reward."
DS9: "Prophet Motive"
Other False Rules
286 "When Morn leaves, it's all over."
Quark, DS9: "The House of Quark"
299 "Whenever you exploit someone, it never hurts to thank them. That way it's easier to exploit them the next time."
Neelix, VOY: "False Profits"
No number "When no appropriate rule applies, make one up."
Arridor, VOY: "False Profits"
No number "When the messenger comes to appropriate your profits, kill the messenger."
Arridor, VOY: "False Profits"
See Also
Ferengi Ship Classes - from all eras
Enterprise Continuity Problems - where the series is in contradiction to established history
Credits
Some screen caps from TrekCore. Thanks to Dan Carlson for some additions.
