For three times already we have been Couch Surfing during this trip. Was in Budapest, then in Zamosc and now in Lublin. Tomorrow we will go to Warsaw, again meeting someone new.
Couchsurf.com and hospitalityclub.org are two nice websites where people can share their couch for others to surf on. It makes the trip much cheaper (usually sleeping is about 50% of the budget) and at same time you meet someone local who can show you around or give you tips.
We were lucky already to meet Gary in Budapest who show us around and let us use the public transport without paying; Michal and his brother (plus the whole family including 3 other brothers, parents and girlfriend) in Zamosc, who made us feel in family again; Adam in Lublin, with his parents, who had everything prepared for our arrival, with maps and information about the city for us. Thanks to all!
For sure not always we will be using couchsurfing, as we also need sometime for us and also because it takes time to find a person. We like to read their profiles and have something (besides traveling) in common.
But yes, I recommend a lot to try it. Myself I received people (including over Xmas last year, Ray from Singapore) and was at peoples place in Europe, Asia and South America.