The very first quilt I had longarm quilted by someone was 15 years ago, it was king sized and cost me $385. I did not expect that, had never had one done before. I imagine he charges a lot more now than he did 15 years ago. I found out later he is a fairly well known Quilter I see quilts he has quilted in shows a lot. I had no idea back then. I have to say- price depends on a lot of things. Location, the Quilter’s experience, style, materials, thread, lots.
Some Quilters charge by the square inch, some by the project, some do pantographs, edge to edge only, some free hand everything, some do mostly ruler work, some have computerized machines and do a lot different quilting. There are lots of differences and lots of different prices.
I've done a lot of long distance quilting for customers- they ship me their top and backing. I generally provide the batting (for a fee) just so they don’t have to ship it. We always discuss everything, and they sign a contract and send a deposit. When their quilt is done I take pictures, send them with the invoice. They pay- including postage and insurance and I send the quilt back. For some customers it has been less expensive for them than local , for some they may pay me a little more but like my work, or have a deadline I can meet that a different person may not be able to meet. There’s always lots to consider. Shop around ( locally and long distance) and see what will best meet your needs. But I do recommend checking out who is local first- just always nice to be able to see your Quilter, see their work, get to know them. Choose someone who can answer all your questions.