For king-sized beds, comforters vary greatly. You can buy a comforter that is already covered (typically stuffed with cotton fill), a silk comforter, or even a down comforter, made of goose down or some other feather fill. The goose down comforter is the most common, and can be used with or without a separate duvet cover to protect it.

Buying a set that includes a comforter, cover, and/or sheets (sometimes called a Bed-in-a-Bag set) is often a great idea to help you coordinate your bedroom and save you a bundle of money in the process. Whereas a separate comforter and sheet set can cost you hundreds of dollars for a king bed, a pre-assembled set can often be purchased for anywhere between $80 and $150.

King comforters are made and tested based on several factors. One is their fill power. This is the measurement of how fluffy the comforter is to the touch. The higher the fill, the longer the life of the comforter. Fill power is measured based on how much one ounce of down (or other fill material) takes up in cubic inches. Six hundred is a good quality measurement, 700 and higher is considered excellent, and anything above 800 is of superior quality.

The weight of a king comforter is also a way to judge its quality and durability. The goal of a great comforter is to get the most warmth for the lightest weight so that you don't need a heavy comforter just to stay warm. Again, the higher the fill power, the better. Comforters are classified in three main categories: light weight (for southern climates), medium weight (typical), and winter weight (for arctic or winter climates).