Remove Serta tag
Remove Bedroom tag
Mattresses & Foundations
Remove Mattresses & Foundations tag
Remove King tag
View our full Instagram gallery to shop these styles and more
Check the king size mattress dimensions to make sure it is the right mattress size for you. The average king size mattress length is 80 inches and the average king size mattress width is 76 inches. A king size mattress is great for two adults and especially great if you have kids who have nightmares or animals who refuse to sleep on the floor. RC Willey sells cheap king size mattresses starting at $129.99 and the best king size mattress from Tempur-Pedic, Aireloom and Beautyrest. If you need mattress financing we have a number of payment plans that range from 0% interest to fixed monthly payments.