A king size microfiber comforter can be purchased at many fine retailers. One could go to a mortar and brick store such as The Bay or Sears. As well, Amazon also shows a number that are available in different colors and patterns.
You can find various furniture outlets online that sell and ship king size comforters.
King size comforters are available for purchase from a variety of sources. Online sources include furniture websites and Amazon. Local options can include furnishing stores. Examples include Macy's, Walmart, Bed Bath and Beyond, and La-Z Boy.
One can buy king size comforters online at such sites as Costco, Sears, Bed Bath and Beyond, JCPenney's and Walmart. One can also shop such sites as eBay, Amazon, Overstock and Bedding Superstore.
There are many retailers that carry king size down comforters. Some of the online retailers include Macy's, Overstock, Kohl's, TheCompanyStore, and Bed Bath & Beyond.
Overstock is the store online which sell cheap down comforters to experience true luxury sleeping. The price is dependable of the size of the down comforters.
Walmart carries several brands in king size down comforters. Some brands include Sateen, Beautyrest, Mainstays, Home Essence, Waverly, and Comfort Classics.
The next size would be a California King. It is a foot longer.
If you happen to have a California king (aka cal king), the king sized comforters will be too short. Otherwise, watch the dimensions and the picture on the different manufacturer's packages. Some are just big enough to cover the top of the bed and not hang down to the floor.
Someone can purchase a King sized comforter from a local mattress store that sells comforters of this size, as well as possibly from a local furniture store.
Duvets tend to be on the top of the bed and don't hang down to the floor. It is just a different look, so the covers are smaller.
Both online shops and brick and mortar stores sell king size comforters. To shop locally and still receive a good price, it is best to check out a larger retailer, like Bed Bath & Beyond, Target or Sears. Internet giants like Overstock could yield good results as well.
Walmart is a great place for inexpensive comforters. Bed, Bath & Beyond is also a great place for anything involving the bedroom, and even Ebay has a great selection of inexpensive comforters - though you will have to be careful buying online; the shipping may end up more expensive than the item itself. Buy as close to local as possible.
Of course the comforters will vary a little bit from manufacturer to manufacturer and style to style in how much extra material you get. If you assumed that the comforter was the exact same size as the matress, however, a queen would be 60"x80" and the king would be 76"x80". Although sizes vary from manufacturer to manufacturer, a good rule of thumb is 86"x94" (8084 sq in) for queen and 110"x96" (10560 sq in) for king. In area, that is a difference of roughly 25%.