Do you prefer ? Free or paid traffic

Personally, I think that a combination of both is necessary.

Free traffic requires the SEO learning curve and takes time to implement and get results. You need to focus on the ads you create and publish. It's easy to get tagged for spam.

Paid traffic is best for instant traffic and testing. This also relieves you of SEO problems. You have to search for your sources because I have found a lot of scammers among paid advertising sellers.