There's not much that's easier than setting up a basic 
BULL^TM BRACKETS sawhorse.
  

Select a 2 x 6 of any desired length and lay it on a flat surface. Place a Bull Bracket at each end.

Cut the legs from a 2 x 4 to any length that will provide a comfortable working height and place a set of legs into each bracket.
  

Place the spreader bar between the 2 x 4 legs. Press down firmly to wedge the 2 x 6 lumber between the Bull Bracket and the legs. 
  

Screws or nails must be placed in the holes of the spreaders to secure the legs.