Regarding your concern, we would like to inform you that our themes are web-application which is built on the WordPress.org core that needs self-hosted, not service host
The Squarespace m platform is suitable for static or e-commerce site with very least logical code.
Therefore, it’s not the platform for web application (theme package with business workflow) as EngineThemes provided.
If you need to get started for free, you can try cloud platform hosting like Google Cloud or Amazon web service. (Try Bitnami WordPress).
Hope this could clarify your uncertainty.