500man, here are some realities for you.
At most gliding clubs, you don't just book a lesson, you need to be prepared to spend most or all of the day there at a time. Ratio of time on the ground to time in the air is very poor compared with power flying.
The time on the ground is not all "wasted” as it involves a lot of learning from seeing what other people do, as well as making your contribution to launching the others, just as you get help from them when it is your turn.
Conversion to gliding and reaching a stage of competence where you can do your first cross-country is possible in one season, if you can go for one day most weeks.
Cost per minute flying in club two seaters is not much cheaper than power, but most training flights are quite short. Winch launching is probably harder to learn including catering for all emergencies. All-aerotow launching and learning would be more expensive, per flight, but might be more economical overall to solo standard.
Gliding examinations have to be taken before going cross-country, even if you have all your PPL exams passed (an ATPL at my gliding club had to do them all too).
Hope this helps.
Chris N