i bind quilts for some of my customers, i don't mind doing it, the ladies who ask me to have arthritis and it pains them so to try hand stitching. I charge $20 to do a binding...$30 if it's a really big quilt (king)
it is one of those things i can bring to work with me and work on and i just offer it as a curtesy- not as a money maker. most of my customers are on fixed incomes and i base all of my pricing to accomadate them...to allow them the opportunity to finish quilts (affordably)
i haven't done the math to figure out what your (suggested prices) would come out to; you should probably base it on your location and what the customer base can afford.