1. Volunteer (help others and help yourself)
A great FREE trip!
2. Stay at a friend's place (couch surf)
Staying with a local instead of in a hostel or backpackers is more than just a money saver. It allows you to travel through the eyes of local, to be a part of the culture (rather than an observer) and to uncover the secrets usually hidden from foreigners.
Some extra advice: learn the basics of their language and culture and put a smile on everyones face!