I'm not knocking the sailing school idea at all, but.....
If you are near any sort of organized racing such as a local yacht club, there are always boats looking for eager and willing crew. At the local level it's not uncommon for boats to be sailing shorthanded and the racing is often more casual, so people are quite willing to take on newcomers.
This is a way to find out if sailing is for you, whether or not racing is for you, and to gain skills and abilities with little to no investment required. All that is required is enthusiasm and a demonstrated reliability.
I know I have invited, over the years, dozens of people like yourself to sail with us, many of which have taken us up and gone on to sail/own themselves.
On the flip side there are just as many that say they'll show up and then don't (various reasons, kids, family obligations, rain, whatever) After a couple of those episodes, they usually didn't get invited back.
With luck you'll hook up with some excellent people, learn lots, and be much better prepared when you do take the plunge and buy your own boat.
Another alternative is to ask around, there are often certified individuals offering personalized lessons on their own vessels for reasonable rates, outside of the mainstream schools.