You can sell your ebooks through Amazon's Kindle program or Apple's iTunes Connect, which gives you access to a large majority of the digital-book reading market and the barriers for entry are incredibly low. You don't need to invest lots of money to make this happen, but you do need to invest lots of time, not only in writing the ebooks, but in marketing them as well.
Check with your local bank to see if they're giving away cash bonuses for opening up accounts. Banks run promotions like this all the time, so grab some real cash quickly if you're in need. It won't break the bank (no pun intended) but it will give you a quick $50 or $100 -- maybe even more -- when you really need it. You might need to deposit a minimum amount of cash (usually in the thousands) in order to qualify for these types of accounts (but not always).
26. Services – You can offer a paid service, such as life coaching, blog coaching, goal setting or financial planning. Just be sure to investigate all the legal implications and make sure you’re not claiming to be a professional if you’re not one. With a service like this, you’re basically using your blog to sell yourself. You’ll need to convince people that you’re worth buying and then be able to back up your claims once they purchase your service.
Note: I think the line where readers will push back probably will vary from blog to blog depending upon their readership. For example here on ProBlogger I get a little more negative feedback from readers on affiliate promotions. I suspect ProBlogger readers are a little more tuned into the issue and suspicious of some of the affiliate marketing that goes on around the web.
There are loads of resources for making money online as an affiliate. You could source products from ClickBank, Commission Junction, Rakuten Marketing, Share-a-Sale, Impact Radius and many others. Plus, many of the larger companies have their own affiliate programs as well. Do your due diligence and find the right company with a relevant product or service to your audience that you can sell as an affiliate.
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.