The DotaLoot database has 148 items for Night Stalker, prices from $0.03. Rarities: Rare, Mythical, Immortal. Any of them can be won from DotaLoot cases or claimed for free in the daily giveaways — noticeably cheaper than buying on the market.
You can get Night Stalker items for free in the daily DotaLoot giveaways. The fastest way is opening cases — noticeably cheaper than buying on the market.
The cheapest Night Stalker item costs $0.03. Prices update based on the Steam market.