I would like to ask about the usage of this phrase. Can we use it for human, or only for non living things? Can we use it with mieć, in a possessive context? For example: Mam przyjaciół zawsze pod reka? - or it doesn't make sense?
It does make sense, however, it sounds a bit instrumental, like you were using your friends.
There's another one: być na wyciągnięcie ręki - moi przyjaciele zawsze są na wyciągnięcie ręki - they're always there for you, no hiidn meaning there, sounds much better.