Cold storage solutions would be cheapest if you don’t need to access it often, if you do then Backblaze b2.

Lastly you could do your own backup (drives sitting at a friends of family’s place?)

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It is important to remember that there are scanners running over all IP addresses on the internet and checking for all the new vulnerabilities. So if you are not updating your services and one of your services has a vulnerability that already has an open source module to scan for it, then you are going to get scanned and you are going to get exploited. So it’s not just about having basic protection, it’s also about being really up to date, which not everyone is doing properly.