Yes, both AppDemoStore and Miro offer a Free Trial.
AppDemoStore is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Miro is designed for Large Enterprises, Medium Business and Small Business.
Pricing for AppDemoStore Starts at $20/Month whereas for Miro Starts at $8/User/Month when Billed Yearly.
Some top alternatives to AppDemoStore includes Miro, NinjaMock, Balsamiq, Axure RP, Wireframe.cc, Inspireframe, Stage, Mockup Clips, Device Frames, Zen Wireframe and Mockframe by 500apps.
Some top alternatives to Miro includes Collaboard, Microsoft Whiteboard, WhiteboardFox, Conceptboard, MURAL, Lucidspark, Whimsical, Board, Zoom Whiteboard and Witeboard.