A homemade shower with pressure. 2 gallon sprayer plus a shower head (or kitchen sprayer) and a fitting. Directions are included here. They put in 1 gallon of tap water and 1/2 gallon of boiling water to get the right temp. They are considering painting it black and putting it outside to make a solar shower. Very clever!
Save $50 per year, per person on water heating costs. Save 1700 gallons of water, per year, per person, compared to use of 2.5gpm low flow showerheads ~ http://walkinshowers.org/best-low-flow-shower-head-reviews.html
Inside the shower head is a plastic or rubber washer that restricts the water pressure and causes it to be less than adequate. If you have recently installed a new shower head, remove it and look into the threaded tube to see if there is a water saving device installed. If so, you can make the hole in the washer bigger by using a drill or completely remove it using a screwdriver. Once removed or made bigger, install it back on the shower and test to see if the water pressure has improved.