If you like the space that a king-sized bed gives you but don’t want to spend the money for one, you may be able to buy two cheap twin beds and convert them into a king-size. There are several kits on the market that let you seamlessly combine two twins into a king-size bed. Since king-size mattresses come with twin-size box springs, there's not much difference in buying two twin beds and combining them with an easy kit.
Buy a converter kit, which pulls together two twin beds to easily create the size of a king-size mattress.
Lay out the twin bed frames and mattresses side by side in the king-size bed frame.
Place the supplied Velcro belt around the two twin-size mattresses to hold them firmly together. Secure the provided buckle around the Velcro so the belt stays in place.
Position the plush centre strip down the middle of the twin-sized mattresses, which will cover the crack to provide a seamless feeling to the mattresses. Attach the centre strip to the Velcro belt to keep it in place.
Cover the mattresses with a protective or memory foam cover, if desired. Then, add a king-size fitted sheet over the bed to create the appearance of a king-size bed rather than two twin mattresses.
Make the bed with the top sheet, and cover with king-sized duvet. To further hide the twin-mattresses, place a valance around the bottom of the mattresses.