Hi

When I goto one shop they give moserbaer DVD for just Rs 10 (R) but on other shop they are selling it for Rs. 20 . I asked them bulk prices and now Rs. 10 costs me Rs. 9 but for SONY DVD R it costs Rs. 15 in bulk for DVD R

Also there is huge difference of DVD RW prices . I need to know what is real cost they are getting for these disks ?

It depends upon what they are selling. Even from same company, there are various types of media and their prices differ so, CD-R from sony can cost Rs. 10 also and can cost Rs. 50 also.

Though I am not sure about their bulk prices, why not you try shops those sell such media to shop owners ie. in bulk , you may get best price there..