This depends on what kind of property you are looking for. Villas and luxury properties or farmhouses with acres of land will be more expensive than a smaller cottage or an apartment. You can pick up a plot of land for under €100,000 and a three-bedroom villa with a huge plot of land for €235,000.
On the other end of the spectrum, Douro offers luxury villas with pools and extensive gardens that are on the market for millions of euros.