(CNN) The real estate market in Manhattan took a sizable hit this summer, with fewer sales and falling prices.

The average sale price for condos or co-ops in Manhattan was $1.66 million during the third quarter, down 14% from last year, according to a report from Douglas Elliman Real Estate. The number of sales also fell 14% year-over-year, marking the lowest third quarter sales total since the financial crisis, the report found.

"This is the worst real estate market we've seen since 2008," said Shaun Osher, founder and broker at Core Real Estate. "The worst for sellers. We are fully in a buyer's market. Now is one of the most opportune times to buy that I've seen in 30 years in real estate."

A tax hike on high-end properties

One reason sales dropped so dramatically was because many buyers rushed to the market during the second quarter in order to get ahead of an increase in the so-called 'mansion tax' that went into effect July 1.

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