i very much doubt anyone would pay premium rate for a chat?... a chat implies 2 way conversation ..why would a stranger be interested in you?
you are not offering them anything except waffle - you are not an expert, and psychiatrist etc...so who would do that?
especially when the samaritans is free
there is also the expectation in these sorts of things to meet up and take things further...
the other problem is they dont know who you are - what if you got into a row? what if they are - or you are - overly opinionated? or judgemental etc
i wouldnt be happy if i rang you and you started having a go at me for my lifestyle or something bad id done...
you could advertise in the paper perhaps...just offer your services to 'chat'...see if you get any takers... you could just add your number and do it unpaid at first , see if you get many takers, and if you do then organise a premium rate number...