So I thought gliding will give me extra knowledge and will be alot cheaper than flying a C150 around
Gliding will definitely improve your piloting skills. In general, any type of flying will improve your piloting skills and the more varied types of flying you do, the better you become. Weren't "Skully" and the captain of the "Gimli glider" all gilder pilots?
But don't expect gliding to be a lot cheaper than powered flying. Until you get to the point where you can fly solo, and have the ability/opportunity to soar for hours on end, gliding, minute for minute, is maybe a little cheaper than powered flying, but not a lot. And you spend an enormous amount of time on the ground being very busy, but not adding a single flight minute to your logbook.
I've done two one-week gliding courses, and the majority of my flights were a winch launch to +/- 500 meters, circling around to find no lift, and back on the ground in six minutes flat. If one winch launch costs, say 15 quid, you're still taking about 150 pounds per loggable flight hour.
Have to admit I have a few 1 hour plus flights in my logbook for that same 15 quid though.