This is my third build and it took about 1/2 a day and cost $50 for lumber and $15 for hardware (decking screws). I previously built Ana's Farmhouse Table and doll farmhouse bed and cupcake stand.
I used the small kreg jig for part of the underseat frame, but it is not necssary. I wasn't using kreg screws so I found it easier to just attach through the end of the 2x4s. I recommend checking for squareness often for this project, especially as the arms and stretcher are attached.