What are the best acquisition channels for B2C SaaS?

Hey folks,

I'm the marketing manager at Rethink Software (https://rethinksoftware.com). Our product, Rethink Files, unifies all cloud files, drives and apps in one file browser. We are currently in public beta and have over 6,000 users.

I would love to hear from your experience: what are some channels that have worked for your B2C SaaS?