For example, if you buy a $100 suit… perhaps you could rent it out for $25 for the night/weekend and someone locally is interested in just a cheap rental (because they don’t need to own a suit for the one or two times per year they wear one). After four weekends of renting the suit, it’s paid for itself. Now, whenever it’s rented out—you’re profiting for the remaining life of the suit.
Theme – you don’t need a special theme for affiliate marketing, you probably just need a blog. I recommend StudioPress themes since that’s what Yoast, Matt Cutts (from Google), and I use. Matt Mullenweg, founder of WordPress also recommends them. One of the biggest mistakes I made was using a theme from Themeforest… since they’re built by independent developers who may stop making updates to their theme. This happened to me and I hear horror stories all the time about people having to switch themes and redesign their entire site. I’ve been using the same StudioPress theme (Outreach Pro) for 3 years. Their themes are lightweight (load fast), SEO-friendly via optimized code, secure, and they have a huge selection of plugins for the Genesis Framework and an awesome community in the Genesis WordPress Facebook Group. They include documentation for setting it up and will serve you for many, many years.
StackPath – CDN with 31 additional data centers (Cloudflare has 150+ data centers, but more data centers = faster content delivery). I get around $1,000/month by referring people to StackPath in my cache plugin tutorials. StackPath recently bought MaxCDN and their affiliate acceptance rate is much lower (depends on your potential volume) but most cache plugins converted to StackPath as their recommended CDN
Our wage and job-growth information come from the latest edition of the Bureau of Labor Statistics’ Occupational Outlook Handbook. The BLS lists “median” wages for jobs rather than “average” wages. The median wage is in the middle of the data set, with half of the jobs paying less and half paying more. BLS job-growth projections are for 2016 to 2026.

If you're serious about making money online, start a blog. Blogging is one of the easiest and most sustainable income sources. As long as the blog is setup the right way, in the right niche, with the right content targeted at the right audience, and the offer is complementary to the content, you could make a tremendous amount of passive income from a blog.