Gregg Bernstein, Senior Researcher at Vox, just published this pretty thorough and awesome description of the tools and methods he uses there for remote testing. Quick summary is below and you can read the full article here.

Calendly for scheduling
Slack for communicating
InVision for testing and collaboration
ScreenFlow for recording
Evernote for note taking
Google Apps for findable, archivable reports.

Note that depending on the size of your organization and the scope of your project, the cost for this entire usability testing routine could amount to as little as $99—a small investment for a large amount of insight.