Step 1: Tools and Materials
A crowbar, wonder bar or nail puller.
A claw hammer.
A tape measure.
A speed square.
A a skill saw.
A drill bit, for pilot holes, the same size as your screws shaft.
A screw bit that fits your screws.
2 ½ or 3" and 1 ½ screws. Coated, galvanized, or not, your call.
A stack or so of pallets.
If you have better, different, or want to use store bought # 1 pine that's cool. I used pallets because they are free for me, and cheap for anybody. If you buy pallets be somewhat picky. Pallets get used hard, often the wood they are made out of is not of decent quality for anything but pallets. Pick good pallets.
Step 2: Cut list
I use my speed square as a saw guide. Fast and easy.
From the 2x4s:
2 at 9" at 22% on both sides (7¾" on top and 9" on bottom).
2 at 12" as square as you can.
4 legs Your call here, 30 is standard,I cut mine for about a 36” sawhorse so my legs are 34” you could cut one of the ends at 22% for a fine fit. I didn't but it would have looked nice.
From the 1x4 slats:
2 4' inch wide, thickness is not critical, at your desired length. They are your sawhorses, you get to pick how wide they are. Try for good pieces as these will be the tops of your sawhorse (splinters hurt) 4' inch wide, thickness is not critical.
2 more at the same length for optionaly bracing of the legs.