Considering that SEO is so expensive with hiring people, would anyone consider it still better than things like PPC (pay-per-click)? Anyway, though, one idea is you can SEO your site and then it will just pull in money naturally without putting more money into it. However, though, some SEO companies need money to keep the SEO running. In other words, there is no end to the payments. However, I could be wrong. Perhaps that's not the norm.