Newbie Question VAT and CST

Hi All,

I am a newbie  to this forum. I need clarification on VAT / CST from experts like you guys.

lets assume that I have small propritership company in tamilnadu and I buy goods from karnataka, What sort of tax will attract the purchase That I am making?

will it be 

1. VAT + CST + Excise Duty

2. CST + Excise Duty

3. Just CST

I read few articles but couldn't understand fully on this subject. Can someone clarify my doubts and point me to any good article which can further enhance the understanding on this subject.

Regards

Vijai .G