Both In my opinion, both of them are needed for your bussiness. The most important thing you need to know is when or where to use free/paid traffic. Without any experience, it's hard to make your campaign run well as you think.
Both are good in their own way and both have few restrictions. Paid marketing is good if you are looking for high volume traffic in a short span of time, while free marketing requires more time and efforts. However, results delivered by free marketing are more reliable. On the other hand, paid marketing is also the ideal option for seasonal businesses. Please feel free to ask if need detailed explanation or help!
Both are effective and really helpful. However, make sure you choose the right paid advertising for your business - mind you, some are scams and just take your cash without delivering results.
In my experience, organic content marketing needs longer but brings the better users - especially for B2B companies. We mainly use blogging to get highly valuable users to our site and afterwards retarget them with paid ads.