Not Pretty, but free.
Remnants of a pile of treated lumber from a deck I tore down sitting around for a few years. Decided to build a "permanent" hammock stand. Problem is nothing of the right dimensions. Longest 4x4 were ~9ft. Frost line rarely goes below a foot, but the soil is sandy. Need some bracing. Couple each of 7' & 6' lengths limited my span to ~12 ft. Scabbed together a 7' & 6' lengths per side. Dropped the posts into ~40" holes. Works, ugly but free.