As said before PayPal is the best option for the International clients and for the domestic customer (India) you will get n numbers of options. But I will suggest you Udio payment gateway and supports only domestic payment.
I will suggest you a few things that need to be considered before integrating payment gateways on your website.
1) Mentioned detail information about us, contact us, terms and conditions of the product, guaranties and warranties and much more.
2) Utilized SSL certificate on the payment processing pages. If you have hosted gateway then make sure that SSL has PCI scanning feature.