If you plan on entering contests and signing up for various freebies online I suggest making an email address just for that so in case you get spam or a lot of offers.
For instance if you sign up for InboxDollars you get emails (this is how you make money off it) so you don't want those emails crowding up your personal email account that your family and friends use to email you. Same goes for newsletters, contests, samples etc. it is a good idea to have a seperate email account for those.
InboxDollars is a very easy way to make a little extra cash. Pretty much you just click on emails and you get paid for it. No, not a lot I am talking pennies but if you do a survey here and there you make anywhere from 50 cents to 1.50. Also if you sign up for things (some free some not) you make money off of those. So far I have close to $30 and I have never bought anything and have done maybe one survey. Hey, it's free money right?