If you drive around Riverside Park Industrial Estate, a lot of companies leave their used pallets outside their units or near skips for people to use. Some are brand new, but some are slightly damaged, and might need a little repair job doing to them.
You may have a problem, however, with taking the pallets apart without breaking up the slats. They use nasty little 'threaded nails'. Have a close look before carting them away, you'll see what I mean.