I wanted to add wheels to my hammock so I could easily move it into shade throughout the day. Some openscad later and came up with this little bracket. Uses a clevis pin for an axle, and just pops into the metal tube feet of the hammock.
I just bought them from Harbor freight. I put links on the printables page to what I used, but they're 6 inch cart wheels, you can get them lots of places. The scad file is parameterized so you can modify it to fit whatever wheels and pins you find.