Welcome to the Board. Your quilt is amazing!! I would really have no idea what you should charge other than to say "quite a bit.". There is an unbelievable amount of work in your quilt. My only suggestion would be to visit the website
www.Etsy.com. If you have never been there, it consists of probably thousands of individual shops, each selling handmade items, supplies for crafts or vintage items. Do a search of handmade quilts and check the items that come up. You can compare the size and amount of work in their quilt to yours and maybe get some idea of pricing that way. I know it will be well over $500. Good luck!!