Unless you're lucky enough to have friends or family conveniently located, planning a trip means sorting out where to stay. For a budget traveler, there are a few good places to start:
Hostels

As a solo traveler, hosteling can be the way to go. If you don't mind sharing a room, you'll likely land the cheapest bed and might even make some friends. Hostelbookers and Hostelworld are my two favorite sites. Both offer user reviews of hostels based on a variety of criteria, including atmosphere, location, security, and cleanliness. Choose your priorities, run a search, and generally don't stray below 70-80% overall ratings. I've had a lot of good experiences this way.
Couchsurfing
For the brave of heart, and ideally, the budget-traveling duo. Couchsurfing is a concept where people offer to open their homes to you totally free of cost. (Nice mannered guests should think to bring a small host(ess) gift.) As a traveler, finding a host can be a big time sink, what with searching through lots of host profiles and writing individualized request messages, but it can result in a really personal experience and a chance to get the most "insider" perspective on the town. You can't be too picky, though, so you may end up in a less-than-central part of town and you might sleep on the floor. It's easiest to find accommodations in lower-requested locations, not major cities where hosts can be overwhelmed with requests. Not recommended for those with some extra cash nor for female solo travelers (sadly, in my experience).
Airbnb
This is undoubtedly my new favorite way to travel in a couple or with a group of friends. It can even be a solution for off-the-map destinations with few (if any) hotel or hostel options. With Airbnb, locals open up their homes—sometimes just a spare room, sometimes the whole place. Users, both hosts and travelers, are vetted through the site's security system, to which they must submit some form of state ID. People who host or are hosted by users have the opportunity to leave a review, so you can get a feel for who the person is and what their home is really like. Airbnb homes range from young couples or empty nesters with a spare bedroom to the lucky ones who have a second home that's not always in use. Personally, when I'm exploring a new city with just one other person, I love to go the spare room route in hopes of getting to hear an insider's perspective from my hosts. I've also taken advantage of full homes to enjoy a get-away weekend with a group of friends. The experiences are always unique and often much more charming than your standard hotel.
Hotels are always an option, and can even be called for in the world of budget traveling under certain conditions, say in remote places, for last minute bookings, or when someone else is footing the bill (say, when your airline goes on strike and they cover accommodations due to canceled flights). Loads of search engines exist for this. I have tested Kayak and Hotels.com, but hotel travel has never become my area of expertise.
Whatever your tastes, as Ray Bradbury wrote in Fahrenheit 451,
Hostels


Couchsurfing
For the brave of heart, and ideally, the budget-traveling duo. Couchsurfing is a concept where people offer to open their homes to you totally free of cost. (Nice mannered guests should think to bring a small host(ess) gift.) As a traveler, finding a host can be a big time sink, what with searching through lots of host profiles and writing individualized request messages, but it can result in a really personal experience and a chance to get the most "insider" perspective on the town. You can't be too picky, though, so you may end up in a less-than-central part of town and you might sleep on the floor. It's easiest to find accommodations in lower-requested locations, not major cities where hosts can be overwhelmed with requests. Not recommended for those with some extra cash nor for female solo travelers (sadly, in my experience).
Airbnb
This is undoubtedly my new favorite way to travel in a couple or with a group of friends. It can even be a solution for off-the-map destinations with few (if any) hotel or hostel options. With Airbnb, locals open up their homes—sometimes just a spare room, sometimes the whole place. Users, both hosts and travelers, are vetted through the site's security system, to which they must submit some form of state ID. People who host or are hosted by users have the opportunity to leave a review, so you can get a feel for who the person is and what their home is really like. Airbnb homes range from young couples or empty nesters with a spare bedroom to the lucky ones who have a second home that's not always in use. Personally, when I'm exploring a new city with just one other person, I love to go the spare room route in hopes of getting to hear an insider's perspective from my hosts. I've also taken advantage of full homes to enjoy a get-away weekend with a group of friends. The experiences are always unique and often much more charming than your standard hotel.
Hotels are always an option, and can even be called for in the world of budget traveling under certain conditions, say in remote places, for last minute bookings, or when someone else is footing the bill (say, when your airline goes on strike and they cover accommodations due to canceled flights). Loads of search engines exist for this. I have tested Kayak and Hotels.com, but hotel travel has never become my area of expertise.
Whatever your tastes, as Ray Bradbury wrote in Fahrenheit 451,
'Stuff your eyes with wonder,' [...] 'live as if you'd drop dead in ten seconds. See the world. It's more fantastic than any dream made or paid for in factories.'