I modified the plans slightly, reducing the overall seating depth by 1.5" so I could use 8' lumber with minimal waste, and make 2 cushions out of one 54" width of fabric. I also tweaked the design to make a chaise lounge on one side. I used bargain priced sunbrella fabric (has a few imperfections) and recycled soda bottle fill for the cushions to keep cost lower. Building the wooden part was quick and easy (took an afternoon including two trips to the store), but this was my first sewing project so the total project time reflects my learning curve making and stuffing cushions.
The lumber cost was less than $100. It was my first sewing project, so I was surprised that the cushion stuffing was the most expensive element of the whole project. If you can find cheap pillows, the plans are easily modified to fit their dimensions.
A narrow roller was a life saver in getting between all of the boards on the seat.