I've seen pricing for pantographs anywhere from .01 to .025 per square inch. A lot depends on the area in which the quilter is located.
As for your batting, it depends on what kind and weight you have. Not all battings are created equal! Some of it is very thin and stretchy, and that doesn't work well on a longarm. Batts that are really thick can be difficult to work with, as well. Let your LA quilter know what you have, and she/he will tell you if it's something that works on the machine.
Most (all?) longarmers want you to give them the top, batting, and back as three separate pieces. There's no need for you to baste them together or pin them in any way. You should make sure that the backing is square and that it's 4" to 6" larger than the quilt top all the way around (the batting should be larger than the quilt top, too). If either your quilt or the backing have a directional design, be sure to let the LA'er know which direction you want it to go.
And be sure to communicate! Hopefully the LA'er will ask you all the right questions about what you want and everybody will be happy, but if you think of something that hasn't been asked, don't hesitate to bring it up.
Good luck!