Any idea about proprietary (70% and 30%) companies?

[masoud]

It is 5 months now i am study bymy self .I am gona to start I find apriapriotary company asking for 300 pounds to let me start trading.is this usual ?do we need to work or start with propriatary companies?it says if I make profit then 70% for me and 30% for them is this usual.?any idea ?do other traders do this ?If you make me clear about this issue appriciate it.
Thanks