Some and any are used when it is not easy or necessary to say exactly the number of something.
Some is for positive sentences. Any is for negative sentences and questions.
- I will buy some beer.
- Have you got any beer?
- You never give me any beer.
(Negative because no beer is given.)
Some is used in questions when we want or think the answer will be yes.
- Would you like some more beer?
(The speaker is offering the listener some beer and would like them to have it.)
Could I have some beer, please?
(The speaker expects the listener to say yes.)