So which one is true?
On average, neither. Unless you're a freelancer, most animation jobs are salaried just like any other. In the United States, entry-level jobs can average from $20,000-30,000 a year, while high-end jobs can break over $100,000. As a median range, though, salaried animators can expect to make $40,000-50,000 a year depending on where they live, where they work, and what role they fulfill on the animation team, as well as their level of experience. This can fluctuate when working in 2D / traditional or 3D animation; it also differs depending on if you're working in cartoon production, movie effects, video games, medical animation and modeling, or several other sectors.
Of course, when you're just starting off low-end or part-time jobs can leave you scraping for pennies. Freelance work, too, can put you in "starving artist" territory. When work is good, it's good, and the clients come pouring in. When it's bad, you're lucky to be able to afford ramen on one low-paying gig a month with clients who always seem to lose the check in the mail. On the upside, freelancers can often set their own rates, and have the freedom to charge what their time is worth rather than accepting a flat hourly rate no matter the difficulty of the job -- which, at times, can make for very lucrative pay. It all depends on the market, the freelancer's skill, and how well they advertise and sell themselves.
When it boils down to it, the answer is just as subjective as salary questions in any other industry. Not all CEOs make millions; not all animators live on ramen and crackers. Odds are, though, if you're looking to build an animation career and head out with resume in hand, you can find a decent salaried position in that average $40,000-$50,000 range.