Powered flying and gliding are pretty much the same cost if you include the hours of labour required. Powered flight involves getting in aircraft and flying it, gliding involves pushing aircraft, launching others, keeping logs, and generally working hard. The balance for this work is made up with the financial cost, gliding is cheaper. Add to this hard work the benefit of good camaraderie and increased fitness and make your choice.
Many power pilots will be surprised at the level of experience amongst the gliding instructor community and their ability as airmen/airwomen in plain and simple airmanship. Aerobatics is not uncommon and spinning is regularly practiced!
So if your dream is centred on the idea of flying long straight legs in an aircraft with autopilot and glass cockpit, all whilst talking professionally to controllers ('cause I hear they give you better clearances then) and following complex procedures then gliding is not for you. Oh and with power you get the chance to go around from a screwed up approach too.
However if you just like flying for flying's sake and if your dream is to be thermalling with a bird of prey on your wingtip, respecting the dynamics of our atmosphere and generally marvelling in the joy of silent flight and the beauty of our world, then gliding might be for you.
I particularly recommend the few moments of quiet elation that overtakes you after your glider rolls to a halt after the landing run, when you are on your own in silence (unless there are skylarks) awaiting the retrieve crew; now that is what I call contentment. Try it....
Jim - who came to gliding early and late......