It's easy to get charged up on vacation--$10 here, $5 there, and pretty soon your credit-card balance looks like the national debt. To keep that from happening, here's a summary of free San Diego activities, most of which are described in detail earlier in this chapter. Many events listed such as the U.S. Open Sandcastle Competition, are no-charge affairs.

Downtown & Beyond--It doesn't cost a penny to stroll around the Gaslamp Quarter, which brims with restaurants, shops, and historic buildings, or along the Embarcadero (waterfront), and around the shops at Seaport Village or Horton Plaza. And don't forget: Walkabout International offers free guided walking tours, and Centre City Redevelopment Corporation's Downtown Information Center gives bus tours.

If you'd rather drive around, ask for the map of the 52-mile San Diego Scenic Drive when you're at the International Visitor Information Center.

The downtown branch of the Museum of Contemporary Art San Diego is always free to the public. And you can fish free of charge from any municipal pier (that is, if you bring your own pole).

Balboa Park--All the museums in Balboa Park are open to the public without charge 1 day a month. Here's a list of the free days:

1st Tuesday of each month: Natural History Museum, Reuben H. Fleet Science Center, Model Railroad Museum.

2nd Tuesday: Museum of Photographic Arts, Historical Society Museum.

3rd Tuesday: Museum of Art, Museum of Man, Mingei International Museum, Japanese Friendship Garden, Museum of the Living Artist.

4th Tuesday: Aerospace Museum, Automotive Museum, Hall of Champions Sports Museum.

These Balboa Park attractions are always free: The Botanical Building and Lily Pond, House of Pacific Relations International Cottages, and Timken Museum of Art.

Free 1-hour Sunday afternoon organ concerts year-round, and free concerts Monday through Thursday evenings in summer are given at the Spreckels Organ Pavilion.

There are four free tours of the park available, leaving from in front of the visitor center.

Although it's a local best-kept secret, the San Diego Zoo is free to all on the first Monday of October (Founders Day), and children under 12 enter free every day during October.

Old Town & Mission Valley--Explore Heritage Park, Presidio Park, or Old Town State Historic Park. A 1-hour walking tour of Old Town is conducted twice daily. There's free entertainment (mariachis and folk dancers) at the Bazaar del Mundo, 2754 Calhoun, on Saturdays and Sundays.

Mission Trails Regional Park, which offers hiking trails and an interpretive center, is reached by following Highway 8 east to Mission Gorge Road.

Mission Bay, Pacific Beach & Beyond--Walk along the beach or around the bay--it's free, fun, and holding hands at sunset is a proven aphrodisiac. Bring a picnic lunch to enjoy on the Ocean Beach Pier or the Crystal Pier in Pacific Beach.

La Jolla--Enjoy free outdoor concerts at Scripps Park on Sundays from 2 to 4pm, from mid-June to mid-September (tel. 858/525-3160).

The half-mile Coast Walk between the La Jolla Cove and Children's Pool is San Diego at its most beautiful--dabble in the tide pools along the way and enjoy the harbor seal colony at Seal Rock and the Children's Pool.

It's also fun to meander around the campus of the University of California, San Diego, and view the Stuart Collection (bring a pocket-full of quarters for the hungry parking meters). The main branch of the Museum of Contemporary Art San Diego is free the first Sunday and third Tuesday of each month. Watching the hang gliders and paragliders launching from the Gliderport near Torrey Pines is a blast.

For the best vista, follow the SCENIC DRIVE signs to Mount Soledad and a 360-degree view of the area.

Coronado--Drive across the toll-free Coronado Bay Bridge and take a self-guided tour of the Hotel del Coronado's grounds and photo gallery. A walk on beautiful Coronado beach costs nothing--so does a lookie-loo tour of the neighborhood's restored Victorian and Craftsman homes.

Farther Afield--Free tours of the ARCO Olympic Training Center in Chula Vista are given year-round. This is the country's first warm-weather, year-round, multisport Olympic training complex. It's on the western shore of Lower Otay Reservoir in Chula Vista, and is one of three United States Olympic Committee training centers. (The others are in Colorado Springs, Colorado, and Lake Placid, New York.) Visitors see a 6-minute film about the Olympic movement, followed by a narrated tour (1 1/2-mile walk) of the 150-acre campus. The hour-long tours are given every hour on the hour, Monday through Saturday from 10am to 3pm, Sunday from 11am to 3pm. Call tel. 619/482-6222 for more information.

To get here, take I-805 south to Telegraph Canyon Road, then go east about 7 miles until you reach a sign directing you to turn right; follow this road to the visitor center.