Yes, both NinjaMock and Miro offer a Free Trial.
NinjaMock is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Miro is designed for Large Enterprises, Medium Business and Small Business.
Pricing for NinjaMock Starts at $7.69/Month when Billed Yearly whereas for Miro Starts at $8/User/Month when Billed Yearly.
Some top alternatives to NinjaMock includes Miro, HotGloo, Pidoco, Balsamiq, Wireframe.cc, Wirify, Claritee, Stage, Mockup Clips and Zen Wireframe.
Some top alternatives to Miro includes Collaboard, Microsoft Whiteboard, WhiteboardFox, Conceptboard, MURAL, Lucidspark, Whimsical, Board, Zoom Whiteboard and Witeboard.