Quote Originally Posted by George1992 View Post
I have another problem.

Could you tell me a difference between the following sentences?

Утром я пойду накупить.
Russians wouldn't speak like that.
Накупить means to buy a lot of stuff.
Quote Originally Posted by George1992 View Post
Утром я пойду за покупками.
Roughly it means "I will go and buy some goods in the morning"

Quote Originally Posted by George1992 View Post
Утром я пойду сделать покупки.
You need imperfective form here i.e. "делать", because it describes a process.
Can be translated as "I will go for a shopping in the morning"