I bought a two room shower tent from Kmart for $36 on sale. It is nicer than the $140 Cabelas model.
For a shower. I used a 3 gallon garden sprayer. Removed the wand. Fitted it with a sink sprayer that is usually used on a kitchen sink to rinse off things. You might have to increase the hose size on the sprayer.
I heat about a gallon and a half of water to boiling, pour into the sprayer and then add the same amount of cold water. Pump it up and you are set to go. You will need to pump up again before done, but you can take a hell of a shower on three gallons of water. Most of the time I have water left.
Total cost: Less than $25 compared to $100 plus for commercial ones that heat and pump the water and need propane and batteries.
Only thing, unless you store it inside, you need to drain and flush all water out after the season so it doesn't freeze and crack the head.
I remember (this was many moons ago) when we used to run a bit low on hot water on board the USS INDEPENDENCE. The brass would institute shower restrictions, that actually work very well, and I use them to this day even though I have plenty of water.
Get in shower, turn water on, and soak down for 3 minutes. Turn off water. Soap body completely. Turn on Water and rinse down for 5 minutes. Turn off water. Get out of shower.
