I am a flute player, maybe I can help you.
1).請問powell 長笛幾多錢?
Powell is one of the brand names well know for professional, they are expensive, but the quality are good, price are depends on models/materials (silver or gold).
2).請問有d 咩長笛牌子呢?我想知多d...
Depends on your level.
Student flute or open hole, Armstrong and Yamaha are reliable brand name, the price is ok.
Professional flutes are much more expensive; Powell, Haynes, Muramatsu, Pearl, Sankyo......