But the idea is you do something you enjoy - so, as you say you like extreme sport but they cost too much, what about volunteering with Scouts.....you get to do climbing and kayaking and so forth, and, along the way, you meet other people, who also share a love of the outdoors.
Or what about a climbing club? My dd does climbing, and, being female, she's definitely in the minority. She goes because she enjoys climbing, but then you get to know people and 'click' with someone.
Most things I can think of, where people share a hobby, also then go to the pub afterwards or arrange meals out or whatever as well as the hobby. However, if you don't meet someone straight off, at least you are doing something you enjoy. You also increase the number of friends you have, and then you get invited to their 'do's' and then you might meet someone who is also looking for a partner.