how to save commission by setting up own broker

i am also thinking about starting my own brokerage firm. the most complex part is to sign up for membership of each exchange and build connection to that exchange, which is too timing and financial expensive. thinking about if I need to trade on 10 exchanges. so, is there any way I use other firm's service to skip this tedious process?

 

Direct your orders to different exchanges.

 

I am not exchange member. How can I send orders to exchange directly?

 

Many platforms allow you to orders directly to different exchanges e.f. to arca . edgx or some dark pools,

 

which platform can do this? do i need to sign up for membership for each exchange I send orders to ?

 

I remember it's pretty easy , open an account through an clearing firm , with 50K$(or 100k?), they will give you 50:1 leverage , very cheap commission (0.0003$/share?).
I got these information from the post on elitetrader.com about 7 years before. but can't find that post anymore.