Looking online for a travel deal? What you don't know could leave you paying too much. 

When Hindi Golden and her family travel, she carefully searches the web for a good deal. She says she'd be annoyed if she found out a travel site wasn't actually giving her the lowest price.

"I probably wouldn't use that site again," she said.

Consumer Reports found just using a different browser can get you a dramatically lower travel deal. The magazine's Shopsmart division searched for the same itinerary at the same time on the Expedia travel site using two different browsers - Safari and Firefox. Turns out one flight was $718 lower using the Firefox browser.

"Travel sites can track your searches. We checked a flight twice on Safari and once on Firefox. And what we learned is that if you check a flight more than once, the cheapest fare can disappear," the magazine's Lisa Lee Freeman said.

Expedia insists pricing is not affected by previous searches. Still, Shopsmart advises removing "cookies" that track those searches. To remove cookies, go to your browser and pick "preferences" then "privacy."

"Another frustrating thing is you find a great rate, but when you click through to book it, the price jumps up," she said.

For instance, a flight to Tokyo on Orbitz went up $29 when Shopsmart tried to book it. And a hotel room on Travelocity jumped up $110.

Being flexible with when you want to leave can make a difference. For example, a family of four going on a spring break vacation to Mexico can save about $400 per person leaving on the Wednesday before school is out instead of the Saturday. It's like getting four flights for the price of three.

So while travel comparison sites offer great convenience, shopping smart means double-checking before you click to purchase.

Another travel-site pitfall Shopsmart found -- the car rental or hotel room offered in a "package" deal may end up costing you more than booking with a hotel or car rental site directly.

With a report from CTV British Columbia's Chris Olsen