I do this because I want to build a solid reputation and a loyal readership of people who trust me. I’d rather make less money and still have a reader than make lots of money and never see the reader again. For me, this comes not only from my ethics but my belief that in the long term building a good profile and reputation leads to other opportunities for profit.
Mechanical Turk: Amazon's Mechanical Turk is a resource for doing human-intelligence tasks, or as the site commonly refers to them, HITs. You get paid a very small fee for any given HIT and you'll need a good deal of volume to make a substantial amount of money. But it is a resource you can use in your spare time to generate a small income online.
My tip: Have one main credit card. Have a second one that you use for necessities – such as groceries or gas – that offers rewards for those purchases (a lot of cards do) and set the second one on auto-pay. You should be able to pay off a smaller amount on auto-pay if it is a necessity. If you think you cannot, then you may need to cut down a lot on expenses.
Freelancing is the next best thing to being paid more for your full-time work, because professional work always pays more than unskilled. To find opportunities, let former colleagues or other personal connections that you’re available for freelance gigs. (Here are some ideas on how LinkedIn could be useful for that.) Or, post on marketplaces particular to your field. For instance, Mediabistro, a journalism site, allows freelancers to post profiles of their experience and services. Though these are more up to chance, designers can bid on jobs at 99Designs.com or submit a design at Threadless, to see if it will be crowdfunded. Elance-Odesk also lists many freelance opportunities, and you can also post your own services on Fiverr, although some freelancers say these services create a race to the bottom on fees and so are not very lucrative. If you're new to freelancing, here's how to set your rates, and here's how to negotiate raises with clients.