I think you'll find the majority of longarm quilters price by the square inch since everyone's "queen" is a different size "queen". Of course, there are also charges for batting, binding, backing, etc. For a basic meander quilting I charge .017/sq inch. For an actual edge to edge quilting pantograph I charge .02/sq inch. Custom starts at .037/sq in and goes up from there. If you are interested, you can check out my pricing on my website- QuiltedJoy.com It is always a good idea, though, to see what the going rate is in your area. Keep track of your time spent working and determine what you are actually making an hour. Operating a longarm machine takes practice and practice takes time so don't lowball your pricing. You are selling your skill and expertise.
I'll get off my soapbox now.