Power levels
Quest for DragonBalls:
Goku: 10
Goku Oozaru: 100

The 21st Tenkaichi Budokai:
Bacteria: 14
Lanfan: 14
Guilan: 71
Yamcha: 73
Nam: 87
Krillin: 97
Goku: 124
Jackie Chun (Kamesennin): 139
Tao Pai Pai: 146
Old Son Gohan: 156
Goku: (after Karin training): 157
Karin: 169

The 22nd Tenkaichi Budokai:
Wolf man: 19
Pam Put: 56
Tsurusennin: 120
Yamcha: 128
Chaosu: 138
Jackie Chun: 139
Krilin: 143
Tambourine: 173
Cymbal: 173
Yajirobe: 181
Tien: 180
Goku: 180
Piccolo Daimao old: 201
Piccolo Daimao young: 260
Goku: 260
Crane's Elder: 120

The 23rd Tenkaichi Budokai:
Chi Chi: 73
Yamcha: 167
Tao-Pai-Pai: 189
Krillin: 206
Tien: 250
Goku: 260
Piccolo Daimaou: 260
Shen (kami-sama): 301

Arrival of Raditz:
Kamesennin's Turtle: 0.001
Farmer with Shotgun 5
Kamesennin: 139
Chaotzu: 145
Yamcha: 177
Krillin: 206
Tien: 250
Piccolo with weighted clothing: 322
Son Goku with weighted clothing: 330
Piccolo without weighted clothing: 416
Son Goku without weighted clothing: 600
Son Goku Kamehameha: 1,000
Chibi Son Gohan: 1 to 1,307
Raditz: 1,500
Piccolo Makkankoupousou: 1,330
Piccolo Special Makkankoupousou: 1,440

Arrival of Vegeta and Nappa:
Chaozu: 610
Son Gohan: 2,800
Krillin: 1,083
Saibamen: 1,200
Piccolo: 1,220
Tien: 1,830
Yamcha: 1,480
Son Gohan healed: 2,500
Son GohanMasenko: 2,800
Nappa: 4,000
Son Goku: 5,000
Son Goku charged up: 8,000
Son Goku Kaio-Ken attack: 12,000
Son Goku healed after Vegeta leaves: 14,608
Son Goku double Kaio-Ken: 16,000
Vegeta: 18,000
Son Goku triple Kaio-Ken: 25,000
Vegeta Gatlit Gun: 35,000
Son Goku Kaio-Ken times 4: 32,000
Son Goku triple Kaio-Ken + Kamehameha: 40,000
Son Goku Kaio-Ken times 4 + Kamehameha: 95,000
Vegeta Ooharazu: 180,000
Piccolo: 3,500

Frieza Saga:
Trunks (Supressed): 5
Krillin: 13,000
Gurudo: 13,500
Kui: 18,000
Son Gohan: 14,000
Dodoria: 21,000
Zarbon: 23,000
Vegeta: 24,000
Vegeta max: 30,000
Krillin after Saichirou-sama charge up: 32,000
Zarbon Monster: 33,000
Vegeta healed after Zarbon fight: 35,000
Son Gohan after Saichirou-sama charge up: 35,000
Rikum: 40,000
Nail: 42,000
Son Gohan healed of Recoom fight: 45,000
Burter: 45,000
Jese: 50,000
Jese Crusher ball: 65,000
Ginyu: 120,000
Ginyu in Goku's body: 23,000
Vegeta healed after Rikum fight: 300,000
Vegeta healed after Freezer fight and Krillin blast: 1,000,000
Son Goku's bursts: 90,000
Son Goku charged up: 180,000
Son Goku without weighted clothes: 200,000
Son Goku healed after Ginyu swap: 300,000
Son Goku 10x Kaio-Ken: 300,000
Son Goku without weighted clothes: 375,000
Piccolo: 400,000
Piccolo without weighted clothing: 440,000
Frieza: 530,000
Son Goku 20x Kaio-Ken: 600,000
Piccolo after Nail merge: 800,000
Piccolo without weighted clothing: 880,000
Frieza form 2: 1,000,000
Frieza form 3: 2,500,000
Son Goku Genki-Dama: 2,500,000
Frieza form 4 at 33%: 4,000,000
Frieza form 4 at 50%: 6,000,000
Frieza form 4 at 70%: 8,400,000
Frieza form 4 at 100%: 12,000,000
Freiza-bot: 12,500,000
King Cold: 13,000,000
Son Goku Super Saiyan: 17,000,000
Super Saiya-jin Trunks: 15,000,000

Past this point - all power levels are estimates.
Android Saga:
Tien: 2,500,000
Gohan: 5,000,000
Super Saiyan Goku (sick): < 10,000,000 (drops
as he gets sicker)
Piccolo: 13,000,000
Yamcha: 13,000,000
Super Saiyan Trunks: 20,000,000
Super Saiyan Goku: 25,000,000
Super Saiyan Vegeta: 27,000,000
Android 19: 40,000,000
Android 20: 45,000,000
Android 16: 50,000,000
Piccolo (after merging with Kami): 50,000,000
Cell (after absorbing humans): 55,000,000
Android 17: 60,000,000
Android 18: 60,000,000
Cell (after absorbing Android 17): 75,000,000
Super Saiyan Vegeta (after room of spirit and time): 90,000,000
Ultra Super Saiyan Trunks: 130,000,000
Perfect Cell : 140,000,000

Cell Game:
Mr. Satan: 127
14-year old Trunks: 5,000,000
17-year old Trunks: 6,000,000
Cyborg Frieza: 18,000,000
Super Trunks: 27,000,000
Super Vegeta: 100,000,000
Trunks after Spirit and Time training: 105,000,000
Super Son Goku: 120,000,000
Super Saiya-jin Son Gohan: 110,000,000
Perfect Cell: 125,000,000
Ultra Perfect Cell: 300,000,000
Son Gohan Super Saiya-jin Level 2: 325,000,000

Majin Buu Saga:
Gohan with Z sword: 360,000
Yamoo: 10,000,000
Supopovitch: 10,000,000
Goten: 30,000,000
Little Trunks: 35,000,000
Android 18: 60,000,000
Super Saiyan Goten: 90,000,000
Super Saiyan Little Trunks: 95,000,000
Piccolo: 180,000,000
Kibit: 225,000,000
Kaioshin: 250,000,000
Gotenks: 250,000,000
Super Gohan: 275,000,000
Dabura: 275,000,000
Super Saiyan Gotenks: 300,000,000
Super Vegeta: 350,000,000
Super Goku: 360,000,000
Fat Buu: 380,000,000
Majin Buu: 390,000,000
Mystic Gohan: 400,000,000
Majin Buu (w/ Trunks, Goten & Piccolo): 400,000,000
Super Saiyan 2 Goku: 401,000,000
Super Saiyan 2 Vegeta: 405,000,000
Super Saiyan 3 Gotenks: 410,000,000
Majin Vegeta: 425,000,000
Super Saiyan 3 Goku: 450,000,000
Kid Buu: 500,000,000
Majin Buu (w/ Super Saiyan 3 Gotenks & Piccolo): 500,000,000
Goku's Mega Spirit Bomb: 550,000,000
Majin Buu (w/ Piccolo, Trunks, Goten & Gohan): 550,000,000
Vegetto: 600,000,000

Bebi Era:
Chibi Son Goku: 2,000,000
Son Goten: 2,500,000
Trunks: 2,500,000
Trunks Super Saiyan: 5,000,000
Chibi Son Goku Super Saiyan: 5,000,000
Son Gohan: 9,000,000
Son Goku: 10,000,000
Vegeta: 10,000,000
Son Goten Super Saiyan: 15,000,000
Chibi Son Goku Super Saiyan 2: 20,000,000
Son Gohan Super Saiyan: 27,000,000
Vegeta Super Saiyan: 30,000,000
Chibi Son Goku Super Saiyan 3: 45,000,000
Son Goku Golden Oozaru: 50,000,000
Son Gohan Super Saiyan 2: 50,000,000
Vegeta Super Saiyan 2: 50,000,000
Son Goku SSJ 4: 160,000,000
Vegeta Bebi-Ooharazu: 165,000,000

Super 17 Era:
Krillin: 3,000,000
Nappa: 17,000
Frieza: 34,000,000
Cell: 35,000,000
Pan: 35,000,000
Android 18: 36,000,000
SSJ Goten: 63,500,000
SSJ Trunks: 63,800,000
SSJ Vegeta: 71,000,000
SSJ Gohan: 72,000,000
Rudou: 73,000,000
Android 17: 77,000,000
SSJ4 Goku: 158,600,000
Super Android 17: 176,700,000
Goku Dragon Punch: 188,000,000

Evil Shenlong Era:
Son Goku: 3,000,000
Son Goku Super Saiyan: 10,000,000
Vegeta: 15,000,000
Son Goku Super Saiyan 2: 25,000,000
Vegeta Super Saiyan: 35,000,000
Son Goku Super Saiyan 3: 50,000,000
All the weakened Shenlongs: 50,000,000
Vegeta Super Saiyan 2: 60,000,000
All 7 Shenlongs: 75,000,000
Son Goku Super 4: 180,000,000
Vegita Super Saiyan 4: 180,000,000
The last Shenlong after absorbing the Dragon Balls: 350,000,000
Gogeta SSJ 4: 360,000,000
Son Goku after merging with Shenlong and absorbing all 7 Dragon Balls: 1,000,000,000

Training
The more training a fighter does the stronger he/she gets. There are amy different ways to train. The most effective way i think to train is to use the hyperbolic time chamber (htc). When in the htc a year goes by, but in the real world only two days have past. Basicly the htc lets you get in a year of training in only two days.

Sayins
Sayins have the ability to double there power very quickly. The only down side to this is that they have to be heald of a body wound that almost kills them. If they are not carefull they could br killed when trying to double there power level. The only person who has ever done this on purpose is Vegeta when he was fighting Freeza.