With the dollar's continuing struggles around the globe, the price tag for any trip out of the country just keeps rising. Even airline tickets, which are generally calculated in the currency of the country in which the journey originates, are subject to a host of increases in taxes and fees, as well as fuel surcharges.

Too often these days, the least expensive way to fly someplace foreign requires sifting through a list of carriers offering round-about routings that entail one or more inconvenient connections and make for long journeys.

But what if you're particular about how you get someplace? You've done research and identified what airline offers the most timely service to your destination. How can you get the best price for the flights you want?

While planning for a trip to England next month, I found out.

Because my destination is the city of Cambridge, about an hour north of London, the closest and most convenient international airport is Stanstead, to which American offers daily nonstop flights from JFK.

With that in mind, I decided to shop online for the best price. After visiting American's Web site, I checked the main online travel services, Expedia and Travelocity, and three aggregator services, Orbitz, Hotwire and Kayak, which search a range of carriers for the best price.

The differences? Not much.

While fare-crunching computers can be creative when it comes to searching out alternative routings, they can't do much when comparing the price of apples to the price of apples.

The lowest fare for my desired journey was on American itself, which quoted a base price of $517 round trip plus an extra $165 in taxes and fees, for a total of $682.

That was the same price quoted by Hotwire and Kayak, both of which simply transfer users directly to the airlines' Web sites. The Orbitz booking engine calculated the base for these flights at $295 round trip, which made my bargain counter click like crazy. However, the $398.65 in additional taxes and fees calculated by Orbitz brought the final total up to $693.65. American figured taxes and fees to be $165, while Orbitz calculated its taxes and fees to be $233.65 more.

Also, isn't it interesting that the add-ons can vary so dramatically, and yet the final prices were only $13.65 apart.

As for the two online agencies, Expedia's price was $687.50, while Travelocity wanted $693.50.

Undoubtedly, all these sites offer a host of other travel products and services that can be of value, but my investigation shows that when it comes to bargains, nothing beats going directly to the airline itself, which in most cases if you're booking online, doesn't tack on a reservation fee, as do the travel agencies. Furthermore, there are a host of other marginal advantages to booking flights directly with the carrier rather than an online intermediary.

Another factor to keep in mind when booking flights online. All these services now offer optional travel insurance to protect your upfront nonrefundable investment in case your plans change after making the reservation — usually a flat fee of $35 to $40 per passenger. Whether or not this insurance makes sense will depend on the circumstances of your trip, but for most travelers, these policies are a bit like extended warranties offered on a wide variety of other products.

While these policies can prove handy for some journeys, most often, they're an unnecessary extra expense, especially since these policies primarily cover only the cost of the flight itself.

Flight insurance does offer some death and disability coverage, but if that's the protection you want, you'd be better buying a long-term blanket policy.

But you have to be a vigilant consumer. Sites generally offer this insurance as an opt-in choice, meaning you must check a box if you want to buy it. On some sites, like Travelocity, this insurance is sold on an opt-out basis. Unless you un-check the box, the cost of insurance will be added to your final charges. In some cases, it's listed as a separate item, meaning you might even be aware of the purchase until it appears on your next monthly credit card statement.

That's one reason many consumer advocates look down on the notion of op-out transactions.

So beware.