In my country, usually 4-6 months prior departing is the best window to find the better air tickets deals. But there are always exceptions.
If you want to travel, don't expect that others do your homework. You started well, asking for advice here, but you also need to join other forums, specific budget travel ones.
You'll need to became an expert in looking for cheap tickets, I believe FT has a part dedicated to it, but you need to master sites like matrix.itasoftware and kayak, playing with dates and destinations. Sometimes the ticket for a particular destination is expensive, but if you try a week or two earlier or later, you may find a good deal. It is time consuming, but in the end I hope you'll get your reward.
Couch surfing and hostels are cheap ways to travel and meet people. In fact, coach surfing is one of the best ways to be involved with locals, if you are luck with your host. But... (There always a but), novices didn't get a lot of replies in the beginning. My advise is hosting yourself (and you will know other people and cultures at home - it may be amazing), and at least in the beginning, my suggestion is looking for coaches offered for novices too. They also want to travel and need the reviews and points you are also looking for.
For my wife, a big part of the leisure trip is the planing part. She usually starts with at least 6 months prior our vacations. And she loves all the research, deal hunting, etc. and the trip too, of course!
And if you'd like to travel and do good, you might look for Peace Corps after ending your training.
Good luck pursuing your dreams! ^