GTA on Own Vehicle

We purchase the goods from A. A charges Rs. 5000 for Material.

Case 1.A uses its own vehicle. Charges Rs. 500 extra as freight. Raises invoice for Rs. 5500, showing Rs. 500 seperately as freight charges.

Case 2. same as case 1 except that freight is not shown seperately.

Case 3. A hire a transporter for delivering the goods at our site. A charge Rs. 500 from us by showing it seperately in the invoice and then pay these Rs. 500 to the transporter.

Case 4. A hire a transporter, raise bill on us for Rs. 5000 only and we make payment of Rs. 500 directly to the transporter.

Query; Now, pls tell me what will be my service tax liability in all the above cases.

My E-mail ID: ca.vineet @ yahoo.in