I assume your'e talking about the reducers. Just take them with you. Odds are the exhaust shop will hand them back to you when they're done anyway. The exhaust shop I use makes their own reducers. They say they get too much leakage from from the ones that come with the headers.
I'd plan on about $275-$300 without h/x pipe. Add about $30 for H-pipe and another $30 or so for an x-pipe if they're fabricating them.