Ever wander how far a Saiyan can go? Im here to tell you now that it can go pretty far.

Saiyan- Saiyans are a ruthless race of warriors. While on there home planet there was an advanced species called Tsufrujins. A war broke out and both sides seamed even. The Tsufrujins were reliable on advanced weaponry and out numbered the Saiyans 10 to 1. The Saiyans on the other hand were extremely powerful and merciless. The Saiyans were also very hard to kill  and often took out many Tsufrujins before going down. Then one night there was a full moon ( A full moon accrued only once in ever eight years on Planet Vegeta) then all the Saiyans turned into the blood thirsty  Oozaru and the Tsufrujins were annihilated. Years to come Freiza found out about the planet and made a deal with the Saiyans. they would go clear out planets and Frieze wouldn't destroy them and he would pay them . Soon Freiza was getting worried that a Saiyan may suprass his Power so he destroyed the entire planet. All but a handfull of Saiyans were abel to excape the planet. Goku, Vegeta,  Nappa, Raditz and in the DBZ movies Taures and Brolly. Eventuly all of them die but Goku and Vegeta are wish backed nourmas time. A normal Saiyans is usely in the one to ten thousands range but it can reach up to three million (Only the best and exceptional warriors can reach such high levels).
                     

Oozaru- In this form the Saiyan are gigantic monkey like creatures with enormous power levels (increasing ones power ten fold). To get this form a Saiyan must have a tail and feel the effects of a full moon ( kinda like a Wear wolf except if you bit someone they wouldn't turn into a Saiyan, in fact you'd probably kill them). If a Saiyans tail gets cut off ( And doesn't grow back) they will not be abel to turn into Oozaru any more. If a Saiyan is already in Oozaru form and there tail is cut off they return to normal. Goku, Gohan and Vegeta use this form.

 
Legendary Super Saiyan: A true SSJ form that gives the Saiyan a BIG power boost. Actually the only Saiyan that is known to have this form is Brolly ( Born with a PL of 10,000!!). This for is stronger than SSJ1. The Saiyans hair turns gold and spikes out,  and eyes are completely white.
                                       
SSJ1: This is the first SSJ level achieved by Goku, It isn't as strong as Legendary SSJ. Actually, the first time A saiyan goes SSJ1 there level doesn't boost as much as you would think. Instead it grows strong the longer a SSJ is in the form, but it dose reach a limit and the power stops to grow (Around eighteen million). Goku, Vegeta, Gohan, Future Trunks, Trunks, Goten and all the fused warriors all are abel to go SSJ1. A Saiyans hair turns gold ( the aurora is yellow gold too) and his eyes turn blue.
                                       
Ultimate SSJ: This is a form that makes a SSJ even more powerful and faster (Speed doesn't increase much). But do to bulkiness it isn't a very useful form unless your fighting an opponent slower than you. Goku, Vegeta, and Future Trunks Reach this level. In this form they  look like nomal SSJ but they are much buffer.
 
Ultimate 2 SSA: This form is stronger and faster than ultimate SSJ. Goku used this form in the Cell games. I think Future Trunks used it also in his time line against Cell and the Androids .
 
SSJ2: This is probably my favorite SSJ level. Gohan is the first to reach this level (In the Cell games). It is much faster than Ultimate 1 and 2, also it is stronger than any of the SSJ forms below it except maybe LSSJ (  . Goku reaches this level in the After life and Vegeta reaches it after being turned into Majin Vegeta. A Saiyans hair is Gold and bolder, his aurora is sounded by Electrical sparks of energy, His hair is a little longer, and his eyes are a lighter blue.
                         
SSJ3: Again a Saiyan is strong a faster than ever. Only Goku and Gotenks reach this level. In this form there hair is much longer that before and there eyes are blue.

Golden Oozaru: When a SSJ turns Oozaru there power is given a major boost (and it gives them the ability to go SSJ4!). Only Goku reaches this level.  Im pretty sure that this pic is Golden Oozaru  but im not totally since this pic is the first time I've ever seen one.
                         
SSJ4: The Strongest (?) SSJ level of all. In this form a Saiyan has a GIGANTIC power level that makes Li Shenron look like a 4 year old. Im not kidding. Actually you aren't even a SSJ, your hair just turns blacker, there hair is alittel longer, they grow hair on there body, there eyes are Yellow and they look just Eviler. Vegeta also Goes SSJ4 but he cheats by using an invention that Bulma makes called the Brute Ray. Also Gogeta and Vegetto go SSJ4. Vegetto is slightly stronger. Im not sure why.
                               
Mystic: A power level that is even stronger than SSJ4!! It isn't much stronger but it still is (and you don't have to get all hairy looking) its never relay figured out how Gohan reaches this power level. Also in Mystic mode ( I think) Gohan can accesses the power of SSA with out acutely transforming into SSA. If you look at the pic below you notice how his hair is just like SSJ2 ( with shorter hair like always) but he doesn't transform. I've seen tones of pics and normal his hair doesn't have one strand on front like SSJ2. Also I think he learns to stay in this form and is abel to conceal its power. If Gohan had trained the whole time that he studied he probably would be abel to surpass any other warrior to ever exists.