For the backpack-toting, smartphone-app-using millennial, here's an easy way to discover and book hostels around the globe.

Name: HostelRocket

Available: iOS, Android, Web

Cost: Free

What it does: It's an ad-free app that lets you search for and book hostels, with more than 35,000 accommodations worldwide. Need a bed at the last minute? Same-day booking is available.

What's hot: Searching on my iPhone was easier than using HostelRocket's website (www.hostelrocket.com). It's a visually appealing, quick-to-use app with hostel photos, reviews, and pricing up front. If you're looking for hostels that surprise and are easy on your wallet, don't miss Casa Alto Vidigal ($12 a night) in Rio de Janeiro, with its remarkable ocean view, or the sunlit New York Moore Hostel ($45) in Brooklyn, with loftlike dorm rooms.

What's not: The review categories are extremely positive - "It's clean!" "Awesome staff!" and "I love this place!" - so if the hostel you're considering has only two stars (out of five), be careful. You might be missing out on a different hostel with a better rating.