Arrival of Radditz

Goku: 416
(with Kame Hame Ha at around 1000)
Piccolo: 408
(with Special Beam Cannon 1300+)
Radditz: 1200
Gohan: 1 to 1307+ (Power raises with his anger)

Later

Master Roshi: 139
Krillin: 206

Fight with the Saiyans

Krilin: 1,800
Piccolo: 3,500
Gohan: 2,000
(when inraged around 3,000)
Yamcha: 1,500
Tien: 1,800
Chaozu: 600
Saibamen: 1,200

Nappa: 4,000
Goku: 5,000
(9000+ when most powered up)
(Kaioken x1: 12,000)
(Kaioken x2: 16,000)
(Kaioken x3: 23,000)
(Kaioken x4: 32,000)
Vegita: 18,000
(18,000 when most powered up)
(Ozaru: 180,000)

Arrival On Namek
Here the Power Levels have been organized into events because the Power Levels change fast

Gohan and Krillin vs Frezza's Scouts

Gohan: 1,500+
Krillin: 1,500+
Frezza's Scouts each at: 1,000

Vegita vs Kui
Vegita: 24,000
Kui: 18,000

Vegita vs Dodoria
Vegita: 25,000
Dodoria: 21,000

Vegita vs Zarbon (1st time)
Vegita: 26,000
Zarbon: 23,000
(when trasformed Zarbon is 33,000)

When Powered up by Guru
Krillin: 30,000

Vegita vs Zarbon(2nd time)
Vegita: 35,000
Zarbon: 23,000
(when trasformed Zarbon is 33, 000)

At Guru's House
Nail: 42,000
Gohan: 37,000(when powered up by Guru)

Gohan, Vegita and Krillin vs The Ginyu Force
Gohan: 40,000
Krillin: 37,000
Vegita: 35,000
Goldo: 12,000
Recoom: 45,000

Goku vs The Ginyu Force
Jeice: 33,000
Baata: 35,000
Goku: (when most powered up 180,000)
Cpt. Ginyu: (when most powered up 120,000)
(in Goku's body 23,000)

Battle with Freeza(form1)
Freeza (form1): 500 000
Vegita: around 120,000
Gohan: 100,000
Krillin: 90,000

Battle with Freeza(form2)
Freeze (form2): 1,000,000+
Gohan (when inraged by Freeza impaling Krillin): 800,000
Piccolo (merged with Nail): around 900,000
Vegita: 350,000

Battle With Freeza(Form 3)
Freeza (Form3): 2,500,000
Piccolo: 1,000,000
Gohan: 1,500,000
Inraged he would be around 2,000,000
Krillin: 100,000
Vegita: 350,000

Battle With Freeza(Form4)
Freeza (50%): 7,500,000
Freeza (100%): 15,000,000
Vegita: 2,000,000
Gohan: 1,500,000
Krillin: 100,000
Piccolo: 1,000,000
Goku: 300,000
(Kaioken x10: 3,000,000)
(Kaioken x20: 6,000,000)
(SSJ1: 18,000,000)

After this point I'm guessing since there are oviously no scouters

SSJ1 Trunks: 35,000,000
Cyborg Freeza: 25,000,000
King Cold: 20,000,000
SSJ Goku: 35,000,000

Vegita: 9,000,000
Gohan: 4,000,000
Krillin: 1,000,000
Piccolo: 6,000,000
Yamcha: 400,000
Tien: 900,000
Chauzu: 100,000

3 Years Later

SSJ Goku: 60,000,000
SSJ Trunks: 60,000,000
SSJ Vegita: 70,000,000

Gohan: 15,000,000
Krillin: 10,000,000
Piccolo: 50,000,000
(Kamiccolo: 110,000,000)
Yamcha: 5,000,000
Tien: 10,000,000

Android 20: 45,000,000
Android 19: 40,000,000
Android 18: 80,000,000
Android 17: 80,000,000
Android 16: 100,000,000

Imperfect Cell 1(Max): 100,000,000
Imperfect Cell 2: 150,000,000

After Time in the Room of Spirit and Time (Hyperbolic Time Chamber)

SSJ Vegita: 200,000,000
SSJ Trunks: 210,000,000
(USSJ Trunks: 290,000,000)
SSJ Goku: 300,000,000
SSJ Gohan: 250,000,000

Perfect Cell: 300,000,000

After Training before Cell Game

SSJ Vegita: 250,000,000
SSJ Trunks: 300,000,000
Piccolo: 200,000,000

Cell Game

Android 16:200,000,000
SSJ Vegita: 300,000,000
SSJ Trunks: 300,000,000
SSJ Goku: 390,000,000
SSJ Gohan: 300,000,000
(SSJ2 Gohan: 450,000,000)