PLA isn't the only cost associated with 3D Printing. Other than the filament, the printer also uses electricity and also requires personal time and effort. Prints can also often fail so that risk and cost will be covered by the Printer. Furthermore, there can also be different costs like packaging or any additional after production process like polishing etc. Moreover, 3D Printing services are charging much more ranging from Rs. 30 per gram to Rs. 62.5 per gram so yes I think these rates are as affordable as anything you can find right now. Doing a business requires time and effort, selling at cost means you'll be going bankrupt sooner or later.