$50.00 out of someone elses sale is good on top of your base.
It helps if you don't look at it in the short term.
Take a longer view of your commission and add everything over a monthly or quarterly period. It adds up to much more than you think. Especially if you are getting a half decent base.
You have to ride out the less lucrative times with a view to the future, build and retain a client network, because you can use those people as a business reference when you have enough experience under your belt to start going for the big money jobs.
Don't be discouraged, stick with it