I saw this really easy craft idea on Pinterest to make a floor lounger using 5 pillowcases and 5 pillows. It was so simple, I had to try it.
I used 5 old pillow cases from the linen cabinet and 5 pillows that have passed their life on the bed. There was 4 seams and the total make time was 20 minutes including ironing the pillowcases (who would normally).
The cost was nil but I think if you wanted to make one with new materials it would be a lot cheaper than buying a bean bag, plus all parts are washable and the pillows can be upgraded at any time.
This is the original - they make it look amazing with such nice pillowcases!