Really, truly, you need to stop thinking of "taking a backup" as just having a copy of your user data files. This is, indeed, one type of backup but it's not the one that will save your keister in the event of a main system drive crash.
External HDDs, which are the best option for long term use for backup and recovery, are dirt cheap. My latest 4TB model cost under $75 when I got it at an after-holiday sale.
Buy a large drive that is capable of keeping the full system image backups you absolutely must take in addition to your separate user data backups.
Ideally, if you have data that's of the "I'd rather die than lose it" level of preciousness, you should have two separate external backup drives, and the one where the full system image has just been taken should be stored somewhere away (as in another building) from the system that's just been backed up, swapping it out with the one that had been used for that purpose the last time. If all your backups are, say, at your house and heaven forbid there were a house fire or flood then your backups go poof along with what they were backing up.