What is the difference between 'qualche' and 'alcuni'?

Both of these words mean 'some', however 'qualche' is ALWAYS singular and 'alcuni' is ALWAYS plural.

Example: 'I have some friends'

Ho qualche amico

Ho alcuni amici

They both mean the same thing!!! Just don't forget to always keep 'qualche' singular, even though it refers to friends (plural).