101Leafy researched the games.
Hunter's Bow I

Low price, entry-level Bow for hunters. Sold in a set with arrows and a quiver.
The table price is the one printed in the book's equipment tables. The shop asks twice that.
Upgrades
| Upgrades into | Hunter's Bow II |
|---|
Upgrade tree from モンスターハンターポータブル 2nd G 公式ガイドブック (Enterbrain, 2008), page 796.
Materials
Brute Bone ×2, Iron Ore ×5, Anteka Pelt ×2