Most adventure tour outfits seem to consider $5,000 a starting price; for these guys, that’s more of a price ceiling. Here is the ultimate list of affordable adventure tour companies.

Small group adventures

partneriExplore (www.iExplore.com) – The number one–ranked website for adventure and experiential travel—and it provides the adventure tour booking engine for everyone from Expedia to the Travel Channel to Frommer’s and Lonely Planet’s websites. Nice spread of trip styles, from traditional tours emphasizing cultural experiences to moderate walking vacations to gnarly physicial adventures. It’s part of the TUI family of 30+ major travel brands, so it incorporates the offerings from its sister Adventure Center, a major player that maintains low prices on hundreds of adventures on all seven continents by contracting with expert local outfitters and other specialist operators. Unlike most tour companies, which stick to cookie-cutter chain hotels, iExplore’s city trips tend to use trendy boutique hotels. Not included: Airfare, meals in cities (except on wine trips).

Sample: $1,195 for 17 days in Borneo, without transpacific airfare but including all internal flights, guides, and lodging from hotels to longhouses to rainforest lodges.

Intrepid Travel (www.intrepidtravel.com) – This fantastic Australian company marries an independent travel style (staying in cheap guesthouses, traveling by public transport) with the expertise of truly knowledgeable guides. It has a larger than usual commitment to sustainable tourism, and tiny groups, often limited to 8-12. When my (anti–group tour) parents found themselves with airfare to Japan and no time to plan, this is where I sent them. Drawbacks: no airfare; many trips have some on-the-ground costs (mostly for meals).
Sample: $709 for ten days in Nepal, from touring Kathmandu and Pokhara to visiting remote villages, mountains trekking, and river rafting; airfare not included.

partnerG.A.P. Adventures (GAP Adventures) – G.A.P. boasts 1,000 trips in 100 countries, from the more tour-like Comfort and Original trips to the gnarlier Active and Overland ones. Drawbacks: no airfare (yet), and quoted prices are not as inclusive as some others (read the fine print to find out about on-the-ground costs, often including most meals).
Sample: $1,695 for 16 days of hiking, biking, and rafting in Spain’s Catalonia region, not including airfare or meals.

Djoser (www.djoserusa.com) – Perhaps since they’re Dutch (and Europeans get longer vacations), Djoser offers longer trips and looser schedules, admirably not trying to pack too much into too short a time. You get to pick your group style: travel with other North Americans or with an international group (some conducted in English, others in Dutch and English).
Sample: $2,930 for 11 days in Ecuador, including airfare from Chicago, three days touring Quito and indigenous villages, and five days of cruising the Galapagos Islands.

REI Adventures (www.reiadventures.com) – America’s greatest co-op chain of outdoors gear stores also offers active vacations. They hit all seven continents, and are better than most at offering a variety of domestic adventures. They also run shorter, 3 to 4–day trips for long-weekenders. It tends to be pricier than most, but with impeccable credentials, and is ideal for those for whom being active is as important as the destination.
Samples: $1,199 for six days of hiking in Death Valley; $1,099 for six days of kayaking the San Juan Islands; airfare not included.

Soft adventure group tours

partnerFriendly Planet (www.friendlyplanet.com) – Excellent company offering inexpensive group tours to exotic destinations around world. If you want to sample some place like China, Peru, Morocco, the Galapagos, Kenya, or Southeast Asia while someone else takes care of all the planning, logistics, transport, meals, and local guides, this is probably the best place to go for the best prices on escorted tours. (In the Small World department, I recently discovered that Friendly Planet is based in tiny Jenkintown, PA, one town over from the equally tiny town where I grew up.)
Sample: $1,799 for 8 days in Egypt and Jordan, inclduing all airfares, Cairo tours, the Pyramids at Giza, the ruins at Petra, and Amman.

Gate1 Travel (www.gate1travel.com) – Another of the best-priced general tour operators out there, offering escorted tours, group tours, and vacation packages to just about every popular country around the world. Like Friendly Planet, it is a generalist agency, geared to people who want to see exotic destinations but do so in comfort and with a guided tour experience. Also like Friendly Planet, the company turns out to have a personal connection I feel compelled to point out, but you should not feel compelled to read, so feel free to skip the next bit in parentheses. (In yet another quirk of fate, Gate 1 used to be from Glenside, PA—which was on the other side of the town where I grew up—and is now based in Fort Washington, which is next to the town where I currently live. However, as with Friendly Planet, I was recommending Gate 1 long before I had any idea it was a neighbor—in fact, I discovered both companies while I was living in New York. None of this has anything to do with booking your trip, but it makes me wonder what was in the water in Montgomery County that made so many of us locals go into travel.)
Sample: $999 for 9 days in Thailand, including airfare from L.A. and a boat trip on the River Kwai.

Overseas Adventure Travel (www.oattravel.com) – This soft adventure tour operator hits all the exotic hotspots, but without as many hard-core activities. Aimed at a slghtly older (40s-60s) crowd (their sister company, Grand Circle Travel, specializes in standard tours for mature travelers). Bonus: GET $50 OFF your trip if, when you book, you give them my name and cusomter number: Reid Bramblett, customer #1545945.
Sample: $2,495 for ten days in Peru, including airfare from Chicago, guides, and nearly all meals over three night in Lima and six on a riverboat cruising the Amazon, with nighttime rainforest walks, piranha fishing, and visits to village shamen.

Active Gourmet Holidays (www.activegourmetholidays.com) – Mixing active pursuits—walking and biking, mostly, with some golf and yoga—with one-day cooking classes, longer cooking courses, wine tasting, and other culinary adventures. Nifty idea—Though far from the cheapest out there.
Sample: $2,600 for 6 days of biking, wine tasting, and cooking classes in Italy’s Tuscany region; air and some meals not included.

Aggregators

partnerReal Adventures (www.RealAdventures.com) – This is not a tour operator or travel agency, but rather a clearing for independent tour operators, local adventure outfitters, and vacation agencies to offer their trips and tours direct to consumers. As such, it offers a potpourri of trips around the world, from single-day experiences to two-week tours, and they run the gamut from balooning or biking to dude ranches, snow-shoeing, sailing, cooking schools, eco-tours, and much, much more.

partnerInfoHub (www.infohub.com) – Not a tour company, rather a kind of aggregator of trips offered by tour companies. it casts one of the largest nets over the industry, listing some 14,000 tours offered by 4,000 operators in more than 100 categories—everything from artists’ workshop to llama trekking, nudist resorts to biblical tours, language schools to personal guide services. InfoHub’s search engine returns results listed by trip rather than by company (for example, it lists nearly 100 bike tours in Italy, but those are offered by just 15 companies). Still, I guess if you could care less the name of the outfitter and are just looking for a selection of 10-day bike tours across Tuscany and Umbria, this is the best way to do it. You don’t book trips directly. You are essentially sending away for a brochure (or a contact) from the actual tour companies.