When to go: Summer is high season for London airfares; you'll find fewer crowds if you travel in fall or spring.

Getting around: London cabs are costly, but the city's comprehensive subway, bus and tram system is a good deal and child-friendly. Don't overlook the front row on the upper-deck of buses-a cheap treat.

Instead of buying pricey single ride tickets (4, about $6.40) invest in an Oyster Card. The card can be topped up with any amount, plus children 10 and under travel free with an adult holding the card (kids age 11-17 get a discounted rate). With an Oyster Card, the maximum adults spend for a day of rides within central London is 6.70 (about $10.75.)

Alternately, purchase a one-, three- or seven-day Travelcard, also valid for unlimited trips. Both cards are available prior to travel through www.visitbritain.us.

WHERE TO STAY

Prices below are for double rooms with private bathroom and include tax and full breakfast, except as noted.

• Four interconnecting houses facing Norfolk Square comprise 60-room St. David's Hotels, a tidy, bustling budget option. No elevators -- a convenience that boosts the price at comparable hotels. Paddington Station is a two-minute walk. Double with private bath, 80 (about $130), 60 (about $96) with shared bath; family rooms that sleep six from 130 (about $210.) (011-44) 20-7723-3856; www.stdavidshotels.com.

• The neighborhood near Earl's Court station, on the Underground line from Heathrow Airport, has plentiful affordable options. The modern Base2Stay offers 67 classy rooms, all with a kitchenette, microwave, wet bar, minifridge, plates and utensils; doubles from 103 (about $165) without breakfast 800-511-9821 or (011-44) 20-7244-2255; www.base2stay.com.

• Near Victoria Station, where Gatwick Express lands, is the charming Belgravia neighborhood. The award-winning boutique hotel B+B Belgravia has small but swank bathrooms, free WiFi and a homey breakfast room with healthy options. Doubles from 120 (about $195) including breakfast, with family rooms priced 150-160 ($241-$260); (011-44) 20-7259-8570; www.bb-belgravia.com.

• In chic Mayfair and overlooking Green Park, the 123-room Athenéum is fresh from an extensive refurbishment that added floor-to-ceiling windows and an upgraded gym. A series of 33 one- and two-bedroom apartments just around the corner are a good bet for families. Doubles from 160 (about $260); 800-335-3300 or (011-44) 20-7499-3464; www.athenaeumhotel.com.

• A two-minute walk from Sloane Square station in fashionable Chelsea, the Draycott Hotel coddles younger visitors with junior-size bathrobes and nightly hot chocolate, and offers deluxe rooms with fireplaces and adjoining bunk bedrooms. Doubles from 245 (about $395) plus tax; 800-747-4942 or (011-44) 20-7730-6466; www.draycotthotel.com.

WHAT TO DO

Many attractions offer discounts for on-line bookings.

• Built in 1999 for the millennial celebrations, the London Eye has gradually emerged as an iconic addition to the city's skyline. On a clear day, this 443-foot-high observation wheel-the world's tallest-offers London's finest view. Tickets 17 (about $27), children 15 and under 8.50 (about $13.65); (011-44) 87-0500-0600; www.londoneye.com.

• The Original Tour gives a decent overview of the city sights aboard a double-decker bus on a two-hour tour. The 24-hour ticket allows you to step on and off at select stops, and your ticket includes a free Thames River cruise and guided walking tour. Tickets 24 (about $38.50); children 15 and under 12 (about $19.25); (011-44) 20-8877-1722; www.theoriginaltour.com.