does having a contract with a listing agent prevent you from buying properties ...

[Mei Zhu]

does having a contract with a listing agent prevent you from buying properties ... directly from owners?

What is my legal obligation to close a property that's not listed by an agent?

I did sign a contract with our listing agent that if I close on a property , I am to pay him 0.5 percent. 

How much percentage am I legally required to pay him even though I found the property myself?

thanks