Buddy up

One of the most economical ways to vacation we've found is to rent a big house with one or more other families. For less than $100 per day per family, for example, we've rented a seven-bedroom lodge near California's Lake Arrowhead for long weekends. The kitchen means we save on restaurant meals, and the presence of all those parents means there's always somebody to look after the kids if you want to do some shopping or see a movie.

A crowd that size may be too big for you, but buddying up with even one other family can make a vacation rental much more affordable. Type your destination and the words "vacation rentals" into a search engine so you can start exploring the possibilities.

Swap your house

We haven't tried this yet, but several friends have, and all reported great experiences. One family swaps only with people they know (or whom their friends know), while others use services like HomeExchange. One person became such fast friends with a couple who stayed at her modest Long Beach, Calif., home that she was invited to multiple stays at their properties in Italy.

Lean on friends and relatives

Hotels give you privacy, a place to retreat and regroup. Sometimes that may be exactly what you need. Staying with good friends or simpatico relatives, though, can really deepen your relationship while saving you some cash. We still remember with fondness the springtime visit we made to dear friends who had moved to southern Virginia. It gave us a chance to reconnect and explore an area we might never have seen otherwise.

Just remember to limit your stay to a reasonable length (remember the old saying about fish and houseguests), and be sure to take your host family out to a nice dinner as a thank-you.

Consider a cruise

Cruising can be a relatively inexpensive way to travel -- not as cheap as camping, perhaps, but more economical than the same-length trip to a theme park. You can find seven-night Caribbean cruises for $500 a person, or even less, in March and April.

The ships typically have pools and kids' clubs. They also have on-shore excursions, which can get pricey fast. Pick yours carefully, and consider exploring on your own when you can. Bonus for you: no cooking or cleaning, and laundry service is often cheap. It gives lie to the idea that family vacations are just picking up after your kids in a different state.

Look for last-minute deals

If all else fails, log on to travel sites to see what you can cobble together without much lead time. Travel providers sometimes slash prices at the eleventh hour to fill airline seats, hotels and cruises. The first time I ever used Priceline we landed a great deal at Paradise Point Resort and Spa, a hotel on its own island right next to San Diego's Sea World. We signed up for the hotel's email list and were sent a great half-price deal we used for last year's spring break. Another auction site if you know where you want to go is Hotwire.

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If you're more flexible about your destination, major travel sites such as Bing Travel, Expedia, Orbitz and Travelocity often feature late-breaking deals. Two other good places to try include Last Minute Travel and Travelzoo's "last minute" section.

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.