I've been using for a while CrashPlan and I've been fully happy about it; unfortunately they decided to switch their focus only for the business sector and ignore the private one.
With a couple of months left of my current subscription, I've started to browse the internet for a decent replacement. The cloud storage services with Linux support and with a decent price (around 7-10 euro/month for a 2-300GB) are quite difficult to find. But it looks like a lot of people are using a nice home-made alternative described below.
First of all you install a local application (like rclone or borgbackup) on your backup server and then connect it with a remote storage like Amazon S3, Microsoft Azure or Google. Of course these are paid services, and they're offering the raw storage, but combined with the first element (the independent software), they make a nice, cost-effective solution.
For my situation, I combined duplicati (installed the latest edge version - 188.8.131.52 for Wasabi support) and Wasabi storage provider. What's the deal with Wasabi? Well, they look like a real alternative for Amazon S3, they have an eye-catching pricing (even cheaper than Amazon - $.0039 per gigabyte per month!!!), a nice web-interface and their service is integrated perfectly with duplicati.
And on Wasabi side of things, we can see a lot of data. Encrypted data that is.
You can find here information on how to setup an Wasabi account to work with your duplicati instance, just keep in mind that you need to generate a new Access Key from Wasabi Web Interface and use the Access key along with the Secret key in your duplicati account.