Tax implications on sale of used object.

Do I need to pay sales tax or any other kind of tax if I sell my used musical instrument at a price say of more than 10 thousand? Actually when I purchased it no cash memo was given to me and while selling it I can not issue any cash memo either. In case the buyer deposits the amount to my savings bank account by electronic transfer and I send the item by courier, will there be any problem in future? Please note that considering prices of purchase and sale, I am incurring a loss. I have absolutely no idea about tax implications of used items. So any advice will be appreciated in this regard. Thanks.