I just did mine--reuse recycle---the last few garbage days I have gathered 6" foam pieces from couches that people have been throwing out. Then i used the electric knife to cut them to size. In order to get the length of foam you need I simply sprayed Contact Adhesive to the foam and they stick like crazy. I then wrapped each cushion with white polyester upholstery fibre. I bought 13 yards of Crypton Ultra Suede from Results for *SUEDE
* $3 per yard plus the same for shipping; still pretty cheap since I am in Canada and they are in Miami. I cut out the pattern with 5/8" seam allowances and for the sides you can either use the box method with zipper panel (go to YouTube to see how they make cushions) ==I opted to go without zippers and just sew them together once the foam was inside. Crypton is a fabric we use in Retirement homes and is very sustainable. I tried the first cushion then called a friend who does upholstery--$300 to sew them. Scamp
sells complete covers in limited ugly colours for $300 for 4" foam. THe bunk portion I used high density foam (camping role)-3 separate pieces-two ends and a middle--this way there is no folding of the foam when sides fold in. I glued foam on (just one side) and covered it leaving bottom open. Slid it in then used velcor to seal it up on the long straight side, Remember to mark where the holes are and poles! Put a small nail sticking out so when you put cover on you can see location. The 6" foam is pretty darn comfy!