Which is the best way to return or sell old engineering books?

There are plenty of online sites where you can register for free and upload the books you wish to sell. Some examples: madbooks.com, allbooksonline.com, secondhandbooksindia.com, etc. However, as you mentioned yourself, you would need to pay the shipping charges to send the books to the buyer. None of the sites make provision for shipping - you have to make the arrangements yourself.

Amazon India does allow sellers to sell books from their site, but I think there is a monthly subscription fee (not sure about this) and you will need to pay a promotional rate for each book sold. Some time back I had read about there being no monthly subscription fee until 30th June, 2015. You can call up this number and make enquiries: 1800-419-7355 (8a.m. to 8p.m.).

If you are willing, you could donate your books rather than sell them.

In our area, we have some book stationaries where we can sell our old books. They buy second hand books from us at 40% of the original price and sell them at 50% to 60% to other students. You should look for such stationaries.

You can simply go to the nearest book store and sell your old books there. You can ask to your friends if they need them. Sometimes your friends may also need your old books for there relatives who are going to study those. Or you can also upload them on the website mentioned by Vandana in her response. But the best way according to me is to go to the nearest book store to sell your old books.

I think it the best to sell your books online. Amazon could be your first preference or you can try any or all of them:

1. www.madbooks.com/
2. www.cash4books.net/sell/engineering-textbooks/
3. www.pustakkosh.com/
4. allbooksonline.com/
5. https://www.quora.com/
6. www.valorebooks.com/books/technology-engineering/

Don't forget to put extra shipping charges and go through the terms and conditions thoroughly before you upload them.

In my opinion, online is preferable, as you cut down in hazards, and increase in the probability of getting them sold across the cities. You get good price and they won't get rotten lying in the godown of some book store, so the condition will remain good till you sell it.

You can try catchabook, Free Local Classifieds for Engineering books from all over India. It is an online classifieds portal to buy, sell and exchange used engineering books. Please have a look and let us know your feedback. Thanks!