After your travel tickets, accommodations are your biggest expense.

Choosing your accommodations is important. You want to feel safe. You do not want to experience bed bugs. You want to sleep well and/or meet people and not break the bank doing any of it.

Whenever you're traveling, try to plan your accommodations ahead of time. You do not need to reserve all the way through -- that takes away from the spontaneity. Try to avoid arriving in popular destinations during peak season without any reservation, though -- you will experience stress.

Both the Lonely Planet and the Let's Go websites list accommodations.