As you probably know, distributing fonts depends entirely on the licenses associated with them. If the license under which you purchased the font prohibits distribution (which it probably will) then you can't send it to the client; they will have to purchase their own license for the font. You can, of course, purchase the license on their behalf and include it in your invoice.

That said, there is a culture of ignoring theses licenses and just passing along the fonts regardless. I would choose the former but some people would be more than comfortable with the latter.