I, like many people have the basic free version of Dropbox which provides a very useful 2Gb of cloud storage but with a few clicks you can increase this to 2.7Gb. Read the Lifehacker posts here and here. Recently the Dropbox team launched a scavenger hunt offering up to an additional 1Gb storage for free although this does require a bit more effort, unless you want to follow some of the walk throughs already posted.
If you don’t have a Dropbox account yet head over to Dropbox and sign up for the free 2Gb account then follow the Lifehacker tips above to get an additional few Mbs with a few clicks. Once done you can start the scavenger hunt by heading over to https://www.dropbox.com/dropquest2011 There are twenty nine steps in total and you cannot skip any unfortunately. have fun.