Make a profit over your total investmemnts in the stock market.

You only need $1 Profit for the Achievement, the Game will explain to you how it's done.
Can also be done at any time after the last Mission of the Game.

However, if you want to earn big Money:

Play until Franklin has an "L" mission on his Radar.
Where you do "The Hotel Assassination" Mission. After that stop going to L(ester) Missions.

The 2nd Lester Mission is where you both sit on a bench and he says "Sit down and look forward.." If you started it, cancel it again!

The Idea with Lester for each Mission is (do with all 3 Characters!):

1. There are always opposing Stocks, you invest in Stocks A
   
2. talk to Lester; start the Mission;
   
3. kill the Target - most likely a CEO of Stocks B
   
4. wait a day or two
   
5. Stocks A go up, Stocks B go down
   
6. sell Stocks A, invest in Stocks B
   
7. wait a day or two again
   
8. Stocks B come back up
   
9. sell Stocks B
   
10. profit!

Remember to wait a few days before selling!

2nd Lester Mission: The Multi-Target Assassination

1. Invest: Debonaire
   
2. do Lester Mission
   
3. sell: Debonaire (75-100% profit)
   
4. invest: Redwood
   
5. sell: Redwood (150% profit)

3rd Lester Mission: The Vice Assassination

1. invest: Fruit
   
2. do Lester Mission
   
3. sell: Fruit (50% profit)
   
4. invest: Facade
   
5. sell: Facade (30% profit)

4th Lester Mission: The Bus Assassination

1. invest: in nothing
   
2. do Lester Mission
   
3. sell: nothing
   
4. invest: Vapid
   
5. sell: Vapid (100%)

5th Lester Mission: The Construction Assassination

1. invest: Gold Coast
   
2. do Lester Mission
   
3. sell: Gold Coast (80-90% profit)
   
4. invest: in nothing
   
5. sell: nothing

Spent a total of $200 million across all three characters.

DONT miss the Guide above or this will be a grind. Buy randomly across all three characters.
Or copy what I bought:

Michael:
gets all the Cinemas and Theaters
$10.000,000 - Doppler Cinema (M)
$20,000,000 - Ten Cent Theater (M)
$30,000,000 - Tivoli Cinema (M)

Franklin:
$2,000 - Downtown Cab Co. (F)
$150,000 - LSPD Auto Impound (F)
$204,000 - Smoke on the Water (F)
$349,000 - Los Santos Customs (F)
$250,000 - Sonar Collections Dock (a)
$275,000 - Car Scrapyard (a)
$600,000 - Hookies (a)
$80,000 - The Hen House (a)
$2,000,000 - Tequi-la-la (a)

Trevor:
$150,000 - McKenzie Field Hangar (T)
$150,000,000 - Los Santos Golf Club (a)

Didn't buy:
$750,000 - Pitchers (a)

Deliver an unsuspecting victim to the Altruist Cult.

Can only be done as Trevor, one Victim is enough for the Achievement

However if you want to 100%+ the game, you need to deliver 4 victims in order to trigger the Random Event Mission: Rogue Altruist

Random Events are indicated by a blue dot on the Map:

• Drunk Driver 1
  
• Drunk Driver 2 (2 People at once)
  
• Snatched: The Lost Girl
  
• Hitch Lift 3: Girl Hitchhiking
  
• Hitch Lift 4: Runaway Bride
  
• Escape Paparazzi: Lacey Jonas

Every other Random Event (aka blue dot on the Map) gives you a major Reward, so stick to the ones above

After four people are delivered, an event is triggered in which Trevor is taken into the camp at gunpoint. He must then fight his way out of the compound by killing all of the cult members.

Rewards:
Rockstar Random Event finished: Rogue Altruist (missable)
4x briefcases around the camp / $25,000 each
1x RPG, Assault Shotgun, Baseball Bat, Body Armor, Health Pack

Batmobile -> Vigilante
Delorean -> Deluxo
James Bond: Wet Nellie -> Stromberg
Knight Rider: K.I.T.T. -> Ruiner 2000
Tron Bike -> Shotaro
Halo: Warthog -> Barrage

Ghost Busters: Ecto1 -> Brigham

• ...

A-Team Van -> Gang Burrito

• Bullbars -> Black Classic Bullbar
  
• Exhaust -> Double Side
  
• Respray ->Black / Torino Red / Graphite
  
• Wheels -> Stock
  
• Wheel Color: Yellow / Orange Smoke

Mystery Machine (ScoobyDoo) -> Bravado Yoga Classic

• Exhaust -> Double Side
  
• Livery -> Surfs Up
  
• Respray -> Bright Orange / Light Blue / Graphite
  
• Skirts -> Arch Extentsions
  
• Wheels -> Muscle -> Azreal
  
• Wheel Color: Yellow / Orange Smoke

Mr. Bean Car ->
Car: Lightning McQueen ->