When it comes to saving money with a low flow shower head you really do not save all that much money with the low flow shower head.
A regular shower head uses around 2.5 gallons of water per minute while a low flow shower may use around 1.5 gallons of water per minute.
So you would only save around 1 gallon of water per minute which is not all that much water when it comes down to things.
Water is pretty cheap to pay for when you have city water and if you have well water it's free except for the electric bill which still is not that bad.
When I installed a low flow shower head I noticed my water bill drop by $1.00 per month which was not that much.
I then put my regular shower head back on and prefer it.