Those prices are on the average side for longarm work. There is a lot of investment and training, and many hours of practice and lots of materials involved in just learning the craft and getting good enough at it to offer services to others.
The price you were quoted was for the quilting - binding is normally extra. It sounds like there was a misunderstanding on what the original quote covered -- or maybe the binding was ordered after the quilting was completed.
Just as an example of costs involved in quilting - I just paid 250 dollars, up front, for two series of FMQ classes at a local quilt shop, and books and materials are extra. The classes are each 125 dollars and are each three days long. So 250 dollars plus probably another 100 dollars or so in material costs, and also car expenses for 6 - 100 mile round trips. It's not cheap learning to quilt -- if one isn't prepared to invest in the equipment and training it's probably cheaper to send your tops out to be quilted.
OTOH, it's a hobby and I think a very rewarding one that eventually may lead one to go into business with it. And most hobbies require investment.
It could be worse -- I could be into golf.
