This is a fairly easy project and at minimal cost. I went the extra mile and ran the boards through a joiner and planer, then routered the edges. This is pretty low to the ground, about 8", but still pretty cool.
Step 1: Garden/patio Bench
(2) 2x4 21" long: Armrest
(4) 2x4 25" long: Legs
(4) 2x4 18" long: Side Support
(10) 1x4 17" long: Trim
(3) 2x6 60" long: Seat
Once you cut out all the pieces, you will need to cut the arm rests and one end of each leg with a 45 degree cut on to make a miter joint. This was a real pain in the ass, so I recommend just going with a butt joint.
When the basic frame is done, add the Side Supports.
Next, add 5 pieces of trim to the outside of the sides.
Finally, attach the 60" long seat pieces and with any luck, yours will come out more level than mine did. I had to shave 1/8 of an inch off of one leg, not to bad really.
I opted to go with pocket screws for a cleaner look, but it was fairly difficult in some areas, especially the miter joint, but if I do this one again, I'm just going to go with wood screws from the outside. Since I wanted to maintain a clean look and pocket screws didn't really work for the side trim, I glued all the pieces on. This should be ok since there is no stress put on them.
I made this at the Techshop in Chandler, AZ.