Cleartrip: I have been using this site for years. Apart from providing competitive fares, they have great customer service. If I find that their fares are marginally higher than the lowest fares I am able to dig out, I still book with them because I know if I had problems, they would help me out.
Goibibo: Check out this site before buying your ticket. There have been times when I have found the lowest fares here.
Skyscanner: This site compares the prices offered by several air ticket booking sites. But of course, not every booking site is registered with them. However, this is quite useful in the sense that you can compare the prices offered by several sites at one go here.
Momondo: I never book my international flights without checking the prices here.
Couchsurfing: A stays in Mumbai and B stays in London. When A visits London, she sleeps on B’s couch. If B has some free time, she hangs out with A. A does the same when B visits Mumbai. No money is involved. This “hospitality exchange network” is a boon for travellers. This site has made it easier than ever to experience a slice of how the local people live. The only downside would be lack of privacy and control over when you want to stay at home and when you want to be out in some cases.
AirBnb: This site, which has become quite popular, helps you get in touch with people who are looking for rent out their homes. The site claims it offers accommodation options in more than 34,000 cities in 192 countries. The advantage of this site is that you get the chance to stay at the home of a local person and pay much less than you’d pay for staying at a hotel. If you are new to AirBnB, sign up by clicking on the link here and get a INR1,563 discount.
Booking.com: I love this site because they have zero cancellation fees on most rooms. Most other sites require you to pay a 12.5 per cent non-refundable down payment.
Agoda: A great site for hotels and guesthouses in the Asia Pacific region. They have a great inventory and offer competitive prices.
Policybazaar: India-based site to compare and choose your travel insurance. I have used it several times myself and the sales guys are pretty helpful.
Lonely Planet guides: Yes, the books are costly. But if you ask me, the amount of info and tips you get in them make the guides worth it.
Rail Europe: Trains are a great way to see Europe and if you intend to do a lot of travelling by train, consider investing in a train pass. While there are several places where you can buy these passes, I have used this one and was satisfied with their prompt service.
Man in Seat Sixty-One: An incredible site on train travel everywhere! Whether it’s a small journey in a new country or an odyssey covering several countries, you will want to consult this site.
WWOOF: The World Wide Opportunities on Organic Farms links volunteers with organic farms and growers. In return for volunteer help, WWOOF hosts offer food, accommodation and opportunities to learn about organic lifestyles. I have not used this site, but I definitely look forward to doing it! This is great for people looking to stay from a few weeks to a few months at a particular place.
Workaway: This is similar to WWOOF, but sounds better because, here, you don’t have to register (and pay) separately for different countries. Workaway claims to have more than 9,200 hosts across the world. This is a great idea for slow and low-cost travel. I have not used this site, but I definitely look forward to doing it!
NOTE: Unless otherwise specifically mentioned, I have used all the resources mentioned here and found them useful.