Use a variable to add the costs of premium features that are selected or deselected using an iOS switch component. See a video of how to do this step-by-step in this webinar: https://support.proto.io/hc/en-us/articles/115001585411-Model-advanced-prototypes-that-use-variables-part-II TAGS: variables variable math addition switch switches fire an items event

I used the Sketch "Delicious" free UI Kit for a food recipes app. It includes 11 pixel-perfect screens. I just added Proto.io interactions and created a great prototype! This Delicious UI Kit was designed by Robert Anitei Sketch source: https://www.sketchappsources.com/free-source/1765-delicious-ui-kit-sketch-freebie-resource.html

A halloween project i have put together using the Proto.io Halloween icon set: https://proto.io/freebies/free-halloween-icons/

A website template with multilevel dropdown menus and scrolling area.

Music App project Design Credits: https://www.sketchappsources.com/free-source/2847-apple-music-app-sketch-freebie-resource.html

A Simple recreation of the Messenger bubble using Proto.io stock images. Basic functions such as drag/drop to screen corners, drag to the bottom to delete, swipe down to reveal 'contents hidden' to bring the bubble back to the screen and tap bubble to show conversation.