Some consider it merely emphasis, viz:
'I ain't got no money' is, really quite clear as 'I have no money'. Only the pedantic would complain that this means you have an absence of a lack of money.
(
The Alchemist king of the needlessly complicated,
Fri 6 Feb 2009, 15:40,
archived)
"some" are incorrect.
and prefer to use correct emphasis, such as:
"I haven't got any money at all."
"I really don't have any money."
"I do not have a single penny on my person at this specific moment in time."
(
drbroon abloooobloobloo,
Fri 6 Feb 2009, 15:45,
archived)