Generally speaking, the full flute is slightly cheaper than the double flute. The single flute is more durable, and the double flute is more suitable for carrying around. When playing, the length can be adjusted with the change of temperature and humidity, which artificially interferes with the sound and timbre.
If you are a beginner, you can buy 200 yuan or so, and beginners can use it all the time at amateur level 7. (This also depends on the individual). Nowadays, industrial flute making is popular, so you might as well buy a Hangzhou Zhongtai or Dunhuang flute as your first choice. Generally speaking, flutes have the names of flute makers, and the market reflects famous flutes, such as Dong Shenghua, Luo Gang, Ding Xiaoming and so on.