Yes, both NinjaMock and Mockflow offer a Free Trial.
NinjaMock is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Mockflow is designed for Large Enterprises, Medium Business and Small Business.
Pricing for NinjaMock Starts at $7.69/Month when Billed Yearly whereas for Mockflow Starts at $14/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 Mockflow includes Miro, NinjaMock, Balsamiq, Axure RP, Wireframe.cc, Mockplus, Inspireframe, Claritee, Stage, Zen Wireframe and Lightning Builder.