It depends on the business.
Generally a combination of Facebook Ads, email marketing, and Google Ads has done well. If you do these well, good rankings in organic search or SEO will happen naturally.
More specifically, if you are selling products with current demand, Google Shopping should be where you start. Then use Facebook Ads to create interest.
Google and Facebook re-marketing ads are great to re-engage with leads to close the sale.
Email marketing is also great to convert leads and to get repeat purchases.
It really works best when you utilize all methods together.
Here is a nice ranking of what works in terms of acquisition and retention courtesy of eMarketer: