Bittertruth, if you don't have knowledge about something them it's better to keep quite. I will tell you why it's in Dollars not in Nrs.

Well you must know that you need a payment gateway to use ecommerce site. Like PayPal , google check out etc
These popular payment gateway doesn't accept Nrs, even though they ate sites which has price in Nrs. You will end up paying in Dollars. You also need NRs in your PayPal account to pay n there is no way u can have Nrs in your account. It's not supported. There are few Nepali payment gateway like e-sewa, payway etc in the sites using these payment gateway u can pay in NRs. But u need to have nepalese Bank account linked to these sites. Or pay hefty fee to transfer from your PayPal. (you will get low conversion rate).

Moral of the story : you are better off paying in dollars ( your local currencies ) rather than Nrs. Or in Nrs if you r in Nepal.