If you have a professional install the Reverse Osmosis System it can cost from $12,000.00 to $18,000.00 which is a lot of money.
What I did instead was to buy the Reverse Osmosis system for $1,500.00 and then have a handyman install it for me for another $500.00 which was still cheaper than what a plumber would charge.
So I paid around $2,000.00 for buying the Reverse Osmosis System and to have the handyman install it.
He said he would do it for less but since plumbers charged more than $500.00 to install it I decided to at least pay him pretty good for installing it as well since he does wonderful work.