CANCUN, Mexico - Even before the heat hits you from the Mexican Caribbean's springtime glory, a blast of ads and brochures and billboards offers nearly endless ways to separate you from your money.

A plastic bag handed out at the airport contains slick guides promoting outings that sometimes rival the nightly cost of a nice hotel. I see it touts the XPLOR cave experience for $129 plus transportation. The Xel-Ha water park is $75, and yes, first you have to get there.

A swim with the dolphins or a lobster dinner on a boat make those day trips look cheap, and there's enough shopping and clubbing and watersports to turn this bargain Mexican vacation into a credit-card buster.

But before the fancy dining, powerboat rides and designer malls arrived, there was already plenty to do along the 80-mile stretch that runs from Isla Mujeres to Tulum, with Cancun and Playa del Carmen in between.

And before the tour buses and $100-a-day rental cars (the cost after you buy all the insurance you'll want), there were plenty of less expensive ways to get from place to place in relative comfort and security.

In a time when people are getting back to basics, there are wonderful experiences, charming towns, outside dining, ocean travel and cultural marvels that make for a low-key vacation in this top spot for Texans.

It doesn't matter where you stay - Cancun and Playa del Carmen are the most popular - because moving around can be easy, cheap and fast enough to fully explore an island, cultural spot or charming town in a day.

So, set aside the bag of coupons of dubious saving, and travel and sightsee the way locals do, stretching your vacation dollars as you go.

-ISLA MUJERES

Just off the coast of Cancun, this laid-back island favors rented golf carts, mopeds and bikes over cabs, and getting there - via ferry - is half the fun.

From Cancun, there are essentially two ways to go via the ferry service UltraMar, which offers inside and outside seating, snacks and even beer for purchase. (www.granpuerto.com.mx; click on "English").

The supercheap way to reach a dock is to take a city bus (which has a prominent R-1 designation above the windshield) for 50 cents that goes from the "hotel zone" to Puerto Juarez a few miles away. A hotel taxi would cost $25 or more.

The wait for the ferry isn't long. Boats leave every half-hour between 5 a.m. and 8:30 p.m., and then every hour from 9:30 to 11:30 p.m. Returns are similar: every half an hour from 5:30 a.m. to 9 p.m. and then every hour from 10 p.m. to midnight. Round-trip cost is 70 pesos, or about 6 bucks.

On the upper, open-air deck, a guitar player strummed a few Mexican tunes for tips, adding to a relaxed, 20-minute ride to the island.

On the return trip, I took the same ferry line, but directly into the heart of the resort area. That's a nice option for safety reasons, given recent reports of local police in the pay of drug gangs and drug-related violence in the city proper, though it hasn't targeted tourists.

To stay within the security of the hotel zone, skip Puerto Juarez altogether and take any hotel zone bus (R-1 or R-2) to Playa Tortugas. There, buy a round-trip ticket. It's twice the price ($15) but still very reasonable, and you land at the same dock on Isla Mujeres.

Trip times are more limited from Playa Tortugas: every hour from 9 a.m. to 5 p.m. for going and 9:30 a.m. to 5:30 p.m. to return.

On the north side of Isla Mujeres, you can shop and explore quaint restaurants within walking distance of the dock.

There are two oceanfront areas: one on the dock side with touristy watering holes such as Senor Frog's and a more relaxing walking area within a few blocks that runs along a sea wall.

Nice beaches are near the ferry dock at Playa Norte and farther south on the island at Playa Paraiso.

Also to the south (which requires a golf cart, moped, bike or taxi) is the Garrafon water park (www.garrafon.com), lighthouse and a turtle park.

In downtown, convenience stores sell snacks, soft drinks, water and beer at peso prices. I saw foreign tourists paying $3 each for beers that cost just 50 cents at the minimarts. (You can walk around with a beer in tourist areas.)

Seafood and other meals at the many sidewalk cafes are reasonably priced and nicely prepared.

-PLAYA DEL CARMEN

Famous for its closed-to-traffic Quinta Avenida, Playa del Carmen was once visited mostly by Europeans looking for cool coffeehouses and local handicrafts. Americans now dominate the scene, although many languages are heard, some of them Mayan.

The town has become more modern, with upscale chain-clothing stores and Starbucks. It's equally populated day and night, with live music and cheap tacos, as well as fancy restaurants. The beaches are white and powdery smooth, offering watersports, on-the-beach restaurants and reasonably priced drinks.

Along the avenue and its side streets is a nonstop mix of inexpensive and medium-priced restaurants and convenience stores.

Near the dock that takes you to Cozumel just offshore are cheap shops where you can buy sunglasses, T-shirts, towels and other last-minute items.

Even with more U.S. chains than in the recent past, Playa del Carmen is a nice contrast to the almost completely Americanized Cancun, which has a more clubby, partying environment dominated by high-rise hotels.

In "Playa," as locals call it, the hip Basico hotel is the place to stay. Its sister hotel, Deseo, is the place to hang out at night, with its upbeat music and fashionable crowd around the poolside bar.

The Blue Parrot is another favorite for nighttime dining and drinking.

A more modern hotel area, PlayaCar, is adjacent to the more traditional town. PlayaCar offers high-rise, upscale, all-inclusive hotels but is within walking distance of the Quinta Avenida.

To get to Playa del Carmen from the Cancun tourist area, take the R-1 city bus (6.50 pesos, or about 50 cents) to the bus station (Central Camionera), where buses to Playa depart every half-hour or so.

The ADO bus line (www.ticketbus.com.mx) features first-class buses with bathrooms. The cost is about $3 to $5, varying because some buses (the GL line) are fancier than others. A street taxi to Playa would cost $40, and a hotel taxi about twice that amount. The last first-class ADO bus to Cancun leaves Playa at 11:45 p.m.

-COZUMEL

An island much larger than Isla Mujeres, Cozumel is famous for the Palancar coral reef off its shore, which provides outstanding scuba diving and snorkeling.

The island offers sharp contrasts, from its supertouristy downtown where most cruise-ship passengers hang out to its beaches such as Palancar that are more European in flavor.

There's also a mix of inexpensive downtown hotels, along with grand resorts farther south on the coast.

Getting there is easy. Ferries from the UltraMar line leave Playa del Carmen from 6a.m. to 11 p.m. and return from 5 a.m. to 10 p.m.

The cost is 140 pesos each way (about $10).

Buses leave from the Cancun bus station. (See the section on "Playa del Carmen" for details.)

Moving around inexpensively on Cozumel is a little more complicated than on the smaller Isla Mujeres or in Cancun with its excellent public bus service.

Moped rentals are popular, but the U.S. State Department warns about their condition, and taxi drivers say there are accidents with cars.

If you are content to stay in downtown, the ferry will leave you right there. If you want to venture out, you'll have to take a taxi, which usually has set prices depending on distance. The Chankanaab reef and snorkel park, for example, is relatively close to the docks, while Palancar is farther out.

Organized tours are available, and they may be a good option if you have the time and want to get a better feel for the island.

Find tourism information at www.islacozumel.com.mx.

-TULUM

Tulum is Mexico's only known archaeological site on a beach, with 60 well-preserved structures within three massive walls (www.rivieramaya.com). The scenery is stunning.

From Cancun, it's a full day's trip: 2 ½ hours each way by bus (carry food).

Organized tours cost upward of $100, and they might be convenient for allowing you to stay for the light show at night (www.grayline.com/Grayline /destinations/mexico/mayanriviera.go).

But you can visit Tulum on your own and save a bundle.

If you get up early enough, you could visit the ruins during the day, have dinner in Playa del Carmen at night, then take a late bus back to Cancun. Total travel cost: less than $20 per person.

The archaeological site closes at 5 p.m., and the last first-class bus from Playa to Cancun leaves at 11:45 p.m.

The ADO bus service sells tickets online (www.ticketbus.com.mx; click on "English").

In the destination box, choose "Tulum" or "Tulum Zona Arqueologica" with more limited times.

The last first-class bus from Tulum to Cancun leaves about 9 p.m., although second-class buses run all night and pass by Playa del Carmen.