for those of us that quilt for others, time is $$. So for each additional task, beyond quilting, I charge. To piece a back (2 lengths of yardage sewn together and pressed) I charge $10. If I have to clip threads, press the top, press the back, trim excess bat/backing or deal with binding, all are extra charges beyond the cents/inch. I do not charge to load the quilt or per bobbin, but know others that do (I roll my time doing that into the cents/inch.) Please keep in mind that a long arm machine often starts used at $10,000, a cone of good thread at $12+, a maintenance call (without problems) at $350 or more depending on travel distance, electricity, etc all add up pretty quickly.
I'd add that pricing often depends on the region you live in and number of quilters available. I even know some that take a loss because they do such a high volume and use cheaper bat, etc.