Just made this sectional following the plans from Ana White.
Roughly $900 CAD in materials, $750 of that being the cushions. I used Duvholmen cushions with Jarpon covers from Ikea, accent pillows I found at Home Sense. All 2x4 lumber and I used pocket holes where screws would be visible. Finished with Ready Seal natural cedar.
Quite happy with it overall. It's really comfortable and will last far longer than (and was cheaper than) those plastic weave ones from big box stores.
I want them to last, so getting both decent quality covers and cushions was key. I've found the cushions on big box plastic sets tend to flatten out pretty quick too, but there were reviews on these mentioning they keep their fluffiness quite well.