Just 20 years ago, you'd have to call an airline to make a flight reservation, buy maps and a travel guidebook to navigate a new city, and consult a phonebook to find a hotel. Traveling has become a lot easier: Thanks to a bevy of smartphone apps, you can find last-minute lodgings and airfare, stay connected en route for free, and even plan your entire trip itinerary with just a few taps on your touchscreen.To help you get the most out of your next vacation, we've scoured the Web for must-have downloads. With the eight travel apps we've listed below, you’ll be able to pack, fly, eat, and find your way like a globetrotting pro. Best of all, these essential apps all cost $3 or less.If you want to book flights anywhere at any time, OnTheFly by ITA Software is a great app to have in your arsenal. This program allows you to find the best possible flight by comparing airlines, dates, alternate departure and arrival cities, and fares. You can also monitor flight prices over time; OnTheFly features a 30-day calendar that allows you to see how trip prices vary by day and week, helping you to find your best travel window. Not since online booking has making an airline itinerary been such a breeze.Packing Pro can help you feel prepared before heading out the door. This app allows you to build customizable packing checklists based on a number of factors, including the number of travelers, the number of days, the weather, and the type of travel. There are more than 800 items in Packing Pro's catalog, but don't worry: not all will apply to your trip. You can also access a pre-trip to-do list, with about 100 tasks for you to check off to ensure you don't forget a thing. And if you have the sort of mom who still reminds you to pack extra undies, you can keep her worries at bay by sharing your packing list with her.When you're at your desk daydreaming of escaping somewhere warm, chances are that you're envisioning swaying palms or a bustling boulevard. You're probably not conjuring images of the time your flight departs, the exact address of your hotel, or the museum's admission price. And yet logistics are just as much a part of travel as the poolside piña colada. Enter TripIt, a one-stop shop for all those pesky (yet important) travel details. This app stores and organizes all of your trip data, from flight information to concert tickets to restaurant reservations. Once you’ve compiled your travel plans, you can forward your hotel, flight, and rental car confirmations to firstname.lastname@example.org, and the app will automatically organize them into your itinerary. Plus, you can share your itinerary with others via email or Facebook. That is what we call "effortless organization."Vacationing can sure work up an appetite, but where to eat? You've probably had the experience of dining at a mediocre restaurant only to walk out of the establishment to find a local gem around the corner. LocalEats is the solution. This free app indexes the best local restaurants (no chains!) in a host of top tourist cities around the world, and allows you to search for a restaurant by cuisine type, neighborhood, price, and more. Never having to settle for a mediocre restaurant when you want an unforgettable meal—Priceless. If you're a fly-by-the-seat-of-your-pants traveler; if you think itineraries are for wimps; if you get a high off of not knowing in what city you'll end up come nightfall; or if you're simply in a bind and need a place to crash, HotelTonight is the app for you. HotelTonight allows you to book same-day hotel rooms at an up to 70-percent discount in top destinations in North America and Europe. And if you're wondering if there's a catch, don't: It's as good as it sounds. Plus, all of the properties on HotelTonight have been personally vetted by the app's creators, so you can rest easy.Sometimes you want to lose yourself in a city, but sometimes you need a guiding star to point you back in the right direction. But why purchase a map when you've got your smartphone? Well, City Maps 2 Go makes the case pretty clear: because you might experience spotty coverage, slow loading times, and restricted data volume, not to mention high roaming charges when using your smartphone or tablet abroad. City Maps 2 Go is a compilation of maps, GPS, and Wikipedia information that is all offline, so you'll have downloadable directions at your fingertips… no matter where you are on the planet.When you look back on a trip months or even years later, what you're usually left with is a general impression. Most of us without photographic memories can't pinpoint our exact itineraries, but wouldn't you like to? With Trip Journal, you can document your days with maps, photos, video, and old-fashioned notes. You can even tag the places you've been so your friends can follow your trail in real time. And because Trip Journal is integrated with Facebook, Twitter, YouTube, and several other social channels, friends and family can stay up-to-date on your travels. We also love its aesthetically pleasing design, which is reminsicent of an old-time scrapbook.Public transit systems can be tricky to navigate, but in many cities, it's also the cheapest and most efficient way to get from point A to point B. The MetrO app takes the intimidation out of the equation by telling you exactly where to get on and off the bus, subway, or tram in more than 400 cities around the world. Plus, this handy app doesn't require an Internet connection. After you install the city you need—Paris for instance—you won't need the Internet to find the shortest route from the Arc de Triomphe to the Eiffel Tower. To that, we say "merci beaucoup!"