Google Optimize is the only 0 cost and hosted tool that I've seen. Unfortunately, you're giving more data to Google. Most a/b tools quickly evolve into paid due

Google Optimize is the only 0 cost and hosted tool that I've seen. Unfortunately, you're giving more data to Google. Most a/b tools quickly evolve into paid due to the nature of their complexity and users. VWO is probably your best bet for low cost and not Google.