What are the best ways to drive organic traffic to an ecommerce store?

Hey guys, I'm currently stuck on a problem.

I help run the ecommerce campaigns for an online shopping aggregator startup (imagine skyscanner but for consumer goods) and I'm having difficulty driving traffic to our campaigns.

Campaigns like "80% OFF your first purchase! Buy one, get one FREE!" - it's mainly different companies trying to promote their discounts.

I've read most of the stuff online and it usually advises running paid ads or doing content marketing.

Besides these two methods, what other method do you suggest or have used to drive traffic to your ecommerce store?

Your answers will be an amazing help.