Dell's online store has a year of Dropbox Plus cloud storage for $60. In addition, you'll get a $25 gift card for Dell.com in your email 10-20 days after your purchase. The $60 price itself is worth consideration because Dropbox charges $100 for the same plan from its online store.
Dropbox Plus's service provides up to 1TB of storage. You can use that space to backup any file you want. Any file stored in your Dropbox folder will be synced with the Dropbox folder on all of your devices, so you can access it anywhere. Plus Dropbox will store old versions of files and deleted files for up to a month. If a device with your Dropbox folder is lost or stolen, you can remotely delete the Dropbox folder.
Dropbox Plus can also upload all your photos for backup. And there's a sharing folder where you can drop files you want to give to someone else, create a link from which they can easily download those files, and set an expiration date for the link so that it no longer works after a set period of time.
The one problem with Dropbox Plus, as with most simple cloud storage solutions like this, is all the privacy encryption is on the Dropbox side of things. While Dropbox promises to keep your data safe from prying eyes, you can't personally cut anyone off from files you've stored with the service. Essentially, if you have really private stuff, you'll want to look into services with more personal privacy encryption. But for 90% of the documents and photos you need a place to store, Dropbox Plus works great.
While this deal is worth it for the $60 price alone, the $25 gift card is a nice little bonus. The gift card is only usable on Dell.com, but the online store sells a lot of things you could spend that money on. For example, you could get a pair of earbuds for $19, a surge protector to protect your electronics, or this tiny Bluetooth speaker for $30. You could also put the $25 down toward something larger, like getting the Blue Yeti microphone for $105 instead of $130, which is a pretty good price.
Dropbox's desktop apps are compatible with OS X Snow Leopard (10.6.8) up to macOS Sierra (10.12), and there's also an iOS app.