If you have $0, your only real option is Social Traffic + Content Locking.
Forget paid ads. Start a YouTube Shorts or TikTok channel in a 'High Demand' niche (like game mods or software tutorials). Show the result, then use a content locker from CPAGrip or OGAds for the link in the comments.
It’s a volume game—your accounts will get banned, so just keep scale-testing with fresh profiles. Once you make your first $50, reinvest that into a domain and some basic automation tools. Don't overcomplicate it, just start pushing traffic.