Dropbox
- Invite a Friend (Up to 16GB): The most common way to get extra storage is to refer a friend. Every person you get to sign up adds 500MB of space to your account. You can get up to 16GB of space with this method, though Dropbox is ubiquitous enough that you probably won't have much like finding 32 friends that haven't signed up for Dropbox. If you want to get ambitious, you can use Google AdWords to promote your referral link.
- Complete the "Get Started" Guide (250MB): Dropbox has a "Getting Started" guide that will show you the ropes. Most of it is routine stuff you'll probably do anyway, but if you do all the steps, you'll add a bit of extra space for nothing.
- Install Mailbox for iOS (1GB): Dropbox has a similar promotion for its Mailbox app. Unfortunately, this one is only available for iOS, however logging in once gives you the space permanently. So it may be worth a quick trip to the Apple store. Just be sure to deauthenticate the device if you use this trick.
- Link your Facebook or Twitter accounts (125MB each): Pandering on social networks for extra space is a little taboo, but you can still eek out a little extra space by connecting your accounts. Though you may be asked to invite other users on the social sites.
- Watch for device bonuses (Lots of GB): If you're in the market for a new device, you may keep an eye out for promotional offers. While they're not always available, Dropbox has offered up to 48GB of space for two years when you log in on a new Samsung or HTC phone. These offers pop up now and then on phones and tablets, so ask about them the next time you're out shopping.
Google Drive
- Use Play Music to store audio: Play Music is Google's storage locker for your music. The company recently bumped its storage limit up to 50,000 tracks, all of which do not count towards your storage limit.
- Convert your documents to Google Drive format: If you're using Drive to store your documents, converting them to Google's formats will prevent them from counting towards your storage limit. As the How-To Geek points out, you can automatically convert documents you upload to Google Docs while uploading to make the process easier.
- Crop photos below 2048x2048: Google allows you to upload an unlimited number of photos, provided the resolution of those pictures is below 2048x2048. A similar rule applies to video below 15 minutes.
Box
OneDrive
- Link your Office 365 Subscription (1TB): While this technically isn't a free option, if you have to use an Office 365 subscription for work, school, or personal use, you're eligible for 1TB of extra space in your OneDrive account. Notably, Office 365 Home includes 1TB for up to five users, so if a friend or family member has the group plan, it may be worth asking if you can join up to get the space.1
- Refer a friend (Up to 5GB): Like Dropbox, you can refer other users to OneDrive to get 500MB for each person you sign up. This bonus is limited to 5GB, but it might be easier to find people who haven't yet activated a OneDrive account than it is to find someone who's new to Dropbox.
- Backup Photos with Camera Roll (3GB): The OneDrive app for Android, iOS, and Windows Phone can automatically backup your pictures to the service. If you enable this, you get 3GB of space for free. You can disable it after that, if you don't want to actually backup your photos, and the space will stay.
- Bing Rewards (100GB): By far one of the biggest storage space boosts is this one from Bing Rewards. Microsoft rewards points for using Bing as your search engine. It may take a while to get the 500 credits necessary—and it only lasts for a year—but free is free.
Sync Unlimited Space with BitTorrent Sync
Sign Up for Other Cloud Services
- Amazon Cloud Storage: The company offers 5GB of free space to all customers. If you have Prime, you can get unlimited photo backup