Prices in general are stable now, after years of increasing.
I believe things cannot go much worse than the current status.
Due to the Greek attitude, some properties are listed for sale for several months, in some cases years, without the owner offering a lower price.
Right now, prices on average are stable but inflation at 5% does the job of effectively reducing their value.

There are exceptions though, with prices still increasing, like Crete.
...there is always demand for Crete!