I have seen PVC light frames for theater installs.. In fact I kind of saved the day for one poor performer who had visions of law suit liability settlements running through his head as a young lady was kicking the leg of the lamp stand then he saw the lights wiggle, and me disappear from my seat.. Shortly I re-appeared in my seat, the lights stabilized and the young lady and her father exchanged seats (I'd been watching too and when the leg came apart I acted.... FAST!!!!!!!)
Basically you make an "H" frame The lamp post mounts in the exact center of the "H" and on the "ends" of the "H" you have an elbow pointing down
you need 4 equal lenghts of PVC for the vertical part of the "H" I would suggest about 2 feet long
Two equal pieces for the "Cross bar" 4 Elbows for the "Feet (note you might use 4 short pieces to make the "Feet" a bit higher if on rough ground) and 3 "T" fittings
Assemble the two cross bar pieces into the ENDS of the T and glue
Assemble a pair of leg pieces into each of the remaining two "T" fittings (Also on the ends) and glue
Glue the "Feet Elbows" on the ends of the leg pieces, so that with the ends of the elbows pointing down the "T" fitting points to the side.
Now you get to the fun part. .Assembly, you have a choice here. Glue 'em on to the cross bar or just friction fit (Gluing is stronger but creates a storage problem... So you either will or will not glue the legs to the cross bar If you can rig a threaded fitting, this is best.
You now have a base. 4 feet (you may need to shim one or two to make it level) with a upward pointing fitting.
The "Mast" goes in here.. If you are going to put a lamp on top (120 volt) you can either run the cord down theoutside or run it through thepipe and simple drill a hole to bring it out just above the base "T"
Again a threaded adapter is good here.. but optional since gravity will hold it in place better.
NOTE: You can (if you use the right size pipes) make a "Sleeve" fitting that is a bit better than just firction fitting the fitting
This requires you use a few more parts though basically you take a smaller pipe, perhaps a foot long (or more) and slide it inside one of the larger visible pipes, glue or screw it so that it extends into the other pipe
I will leave the exact design of this to you.. but basically it's use a short pipe and a straight coupler where the "T" fittings are
(This is for the fittings you take apart and put back together)
Optional method
Drive a metal rod or fence post into the ground
Slip the PVC pipe over it
NOTE: In many camp grounds there are water and/or electric lines just a short distance below the surface.. More than one camper has driven a tent stake and been rewarded with a geyser of water as they punctured a water main