This year I'm making new deck cushions for our Meadowcraft wrought iron deck furniture, purchased in 2008. At the time there was a 15 year warranty on the frames. The frames still look great and I think can go many more years.
The new cushions for the chairs are from CushionSource, "Deluxe Cumuplush" outdoor cushion material cut to order 21" x 22.5" x 4". With tax & shipping it came out to about $34 for each cushion.
The fabric for the chairs is Sunbrella Cultivate Tandoori bought in several pieces from online retailers. Piping for all is a lighter solid weight red Sunbrella bought at Short Sheets.
I found some nice 27" #5 upholstery zippers in dark brown from Wawak.
5/32" polypropylene cording from Sailrite.
Silk film for wrapping - the first piece was 54" from Amazon, then later bought 48" from Baytrim on Etsy. The 48" was plenty wide and easier to deal with.
3/4" dacron cushion wrap to start. I later had to order more and was only able to find 1/2".
3M general purpose spray glue for adhering the cushion wrap to the cushion
Gutterman heavy duty thread for hand sewing the seat back cushions closed
Sailrite hot knife and tempered glass - $140 for the hot knife and $40 for the tempered glass, but I'll be able to re-use this any time I'm working with synthetic upholstery fabric
Covered buttons: Sailrite didn't have the 1-1/8" size snap-together buttons in stock, so I'm re-using the old buttons
Waxed tufting thread from Sailrite
I also have cushions and material for two benches, and materials to make lumbar pillows.
By the time all this was done I spent about $1700. That includes 5 chair backs and seats, my small kidney-shaped bench and small garden bench, and I have a lot of fabric left over because as usual I over-ordered. That also includes the Sailrite hot knife and tempered glass which I'll use in future, fabric for a footstool I'll make one of these days, outdoor lumbar pillow fillers which I'll make into pillows in future, and lots of leftover supplies.