Neither Observable nor Cube.js offers a free trial.
Observable is designed for Individuals, Medium Business and Small Business.
Cube.js is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for Observable Starts at $9/User/Month whereas for Cube.js Starts at $99/Month.
Some top alternatives to Observable includes CodePen, Visualr, ibi Analytics Platform, Instadeq, Dashana, Ideata Analytics, Vizician, Zoomdata and Vizydrop.
Some top alternatives to Cube.js includes Microsoft Power BI, Dundas BI, Draxlr, Dgraph, GraphJSON, Ideata Analytics, Microsoft Power BI Desktop, Metabase and GraphQL Editor.