Yes it is economical. I only replaced them once in 4 years and that was because I did not bring my glass jar with me to Florida and just used distilled water.
I wanted the alkalinity so I bought a new set and bring my jar along now. Since we stay in each house about 6 months and we travel by motorhome, it easy to bring it along.
It is simple to make, you can read the instructions, I bought a glass jar for $5 at Walmart and on the outside I made 2 lines with a magic marker, so I only had to measure the very first time.
In MA the well water has some iron and I have a bag in each toilet tank that takes care of the iron and it should also help the septic tank.
For a while I ozonated my water, but got tired of it. When I use ozone now I do it by insufflation.