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LOS ANGELES (CBSLA.com) — With the start of the holiday shopping season just days away, a consumer group says taking Google along with you to compare prices might end up costing you twice as much.

A Consumer Watchdog study has determined product results returned through Google Shopping to be as much as 67 percent higher, compared to other comparison shopping engines like Shopzilla, Pricegrabber and Nextag.

“People are trusting Google to give the best answer. Well, guess what – it’s not the best answer,” said John Simpson, an advocate with Consumer Watchdog.

The results shown in the Google Shopping box on the right side of the screen after performing a search for, say, digital cameras, are actually products that have paid for top placement.

“The price that’s shown here in this Google Shopping result was not the lowest price in eight of the 14 cases,” Simpson said.

The advocacy group says that Google used “classic monopolistic tactics” to clear the field of competitors, then changed its business model from Google Product Search to Google Shopping, in which merchants had to pay to be included in the results.

A Google representative declined to respond to the study, but did say that price is only one factor for online shoppers.

Simpson says the group plans to bring this study up with the Federal Trade Commission next week, but until then, consumers are advised to shop around.