Simple Mockup Tool. Smartmockups is a remarkably slick solution that negates the need for using photoshop or other tools to get a professional result. The fastest web based mockup tool.

A mockup generator is an online browser based tool which allows you to create product mockups without any third party software such as photoshop. Mockup builder a killing prototyping app. Mockplus is an all in one web ui mockup tools for free that allow you to create mockups for mobile android.
5 best web ui mockup tools for free that you must try 1 balsamiq mockups.
Mockup builder has just recenly been released and looks very promising. Smartmockups is a remarkably slick solution that negates the need for using photoshop or other tools to get a professional result. No experience or skills needed super easy to use. Create professional mockups right inside your browser even on the go.