I use raza.com to buy cards. they have very reliable connection most of the time and give good minutes too. They have card named "dial direct" you simply register your ph no. so you dont need to enter pin no. No service charge, minute rounding, no connection fee, can check call history and I guess they charge 8 cents for Kathmandu and 10 cents for Outside or mobile. I am using it for quite a while and no complain.

**Mostly I call after 9 PM so doesn't kill my cellphone minutes as well.