Kathmandu is the capital of Nepal and the largest city in that country.
At present there are only two major roads leading out of the Kathmandu Valley. One goes northwest to Tibet, while the other leads west to Mugling and Pokhara. If you wish to travel to anywhere in the Terai or cross into India, you must first go west, then turn south at Mugling.
West (Prithvi Highway)
The highway going west from Kathmandu leaves from the Kalkani neighborhood. From the intersection of this road and the Kathmandu ring road here, you can walk up the road less than a kilometer and find a place where a car can pull over.
Alternately take a bus from[Ratna Park to the town of Chandragiri (चन्द्रागिरी) for 50NPR which then offers an easy choice of roads South to Hetauda, or further West towards Pokhara.
North East (Melamchi)
Take a bus from[Ratna Park which will get you as far as Sankhu. From Sankhu make a sign for Shankharapur (शङ्खरापुर), and from there the road splits towards Melamchi. Make sure you don't take the Northern "Piplie" road, as when you get there you'll have a hard time getting out as there's very little traffic.
Most of the stuff on not official stores are fake with lower quality. Dont risk with your life choosing a winter traking gear!!! You can trust more to second-hand stuff
Thamel is full of trekking shops, but you'll find better prices and often nicer gear if you head south towards the local market place named Ason. Tarps can be found (as well as cheap roll mats) on the street named "Jagatsundar Marg", just north of Ason bazar. If you're willing to compromise and get a used sleeping bag, you can find one for as low as 1,500 NPR (12USD).
Check around Ason market for good boots. Look for full leather with a stitched sole. Don't buy any boots where you can't see the stitches as they're likely cheap fakes which are glued together. Buy leather over synthetic. A good pair of boots should be available for around 2,500 - 3,000 NPR.