You can get BOSS Linux version 3 DVDs for free from any of the BOSS Linux Support Centres. All you have to do is call them up and request for a DVD. Be sure to specify your complete address, as the DVDs will be sent through courier.
The details of the Support Centres can be found here(click).
Here is a list of phone numbers, for complete address and other details refer to the link above.
Bangalore 080 – 28523300
Hyderabad 040 – 23150115
Kolkata 033 – 23573950
Mohali 0172 – 2237054
Mumbai 022 – 26201488
New Delhi 011 – 24301313
Noida 0120 – 3063344
Thiruvananthapuram 0471 – 2314412
or if you are in a hurry, this post has the links to the BOSS Linux downloads page.