The two shops selling the Simoco Buddy are Lepcha (Zangto Pelri complex) and a mobile shop on Norzin Lam a few blocks down from the milk booth (contact phone 77236646).
Currently this seems to be the cheapest netbook available in town. Lepcha also sell a Nu. 17,000 Samsung netbook, which I have not tested.
Disclaimer: I have not purchased or used the computer beyond a simple test at one of the shops.