To front money you don't expect to get back, refunded, or applied to future expenses (as in pulling cash out of your pocket).
I wanted to get that fish-food service, but I had to come up with $45 out-of-pocket.
Out-of-pocket is a pimp term. If the ho (whore) is out of pocket that means she is out of line. It could be talking back, not making enough dough (money), scheming behind her pimp's back, or any other non-compliant things. This term can be used for other out of line people that may or may not be worthy enough to be called a ho.
"This out-of-pocket bitch came up short so I had to put a foot up her ho ass."