Good places to look for pavers include Craigslist.org and any neighborhood where extensive renovations are happening. Local classified ads sometimes have postings of free pavers. Freecycle groups are another excellent source for pavers.
Pavers can be brick, flagstone or concrete blocks. Sometimes homeowners and businesses decide that they need new pavers or just want to use asphalt so they take up existing pavers. If you or someone you know has property with stones on it, you can gather flatter stones for use as pavers. Always ask permission before gathering stones from anywhere.
Old tile can be used as a thin paver. Granite tile is especially good for reusing as pavers. Combing multiple types of pavers is often necessary to finish a larger project, but this allows for creative patterns and planning. Old bricks make excellent pavers.
If you know of a house that is to be torn down, you can sometimes get free brick or stones. Concrete capstones are often leftover from building projects and can be used to create a paved surface that is 4 inches thick. Smaller rocks that are flat can be gathered to fill in spaces between larger flat rocks. Free pavers usually don't last long when advertised, so it is important to check ads and boards regularly.