Are these sentence grammatically correct and common use ?
1. They are putting on a party at school and trying to invite students to the party. (Should I use throw up a party ？)
2. Turkey government has started to implement the monetary control due to the huge decreasing of its currency.
3. Turkey's GDP will be in half of its GDP in 2017 that means Turkish people would face the economic high inflation in the next couple months.That will make people;s life miserable in turkey in a long run.

Question

Answer

1. no, never use the term "throwing up" unless you mean vomiting. you can use "putting on a party" "hosting a party" or "throwing a party".
2. Turkey's**
3. "Turkey's GDP will be half of its GDP in 2017 which means the Turkish people will face the high economic inflation in the next upcoming months. In the long run, this will make the Turkish people's lives miserable."

Answer

Here are some suggestions.

1. They are planning a party at school and trying to invite students. 
2. The government in Turkey has started to implement monetary controls due to huge decreases in its currency.
3. Since Turkey's GDP will be half of that of 2017, the Turkish people will face high inflation for the next couple of months. 
In the long run, this will make life miserable for most people inTurkey

Hope this helps