Only boats with less than 15 years, particularly boats with less than 10 years are cheaper in Europe. Older boats are cheaper in US.
There are more recent boats in Europe and more older boats in the US. Besides that in the South of Europe almost all countries are in a big Crisis and that drove prices down....a lot. If you want a recent boat at the best price probably the best place to look is Italy or Spain.
There are some big brokers that will not charge anything to a private owner so boats can be sold at better prices. One of the more known is http://www.cosasdebarcos.com/
For Italy try: