Free space on Dropbox is worth its weight in gold. You get to keep it forever, and every additional megabyte postpones the day when you’ll have to switch to their $100-a-year paid plan.

Thankfully, this week Dropbox is giving away free space if you try their iOS Gmail client, Mailbox (also free). If you have an iOS device, download the app, go to settings, and link it to your Dropbox account. You get the free gig of space immediately.