Pretty stringent rules for someone with maybe $80 total invested.First you need to define "backup". There is a difference between having a second setup, and having a backup.
The second setup is for your convenience, the backup is for if Hell freezes over and nothing seems to work.
IMO if you can't use your backup for a hammer, and still vape it ... it isn't a reliable backup. It needs to be indestructible, but it doesn't have to be the best vape on the planet. It just needs to get you by while you get your regular setups sorted out/replaced.
So your needs are different when looking for a backup, or looking for a second setup.
If you want a second setup ... get what you like.
If you want a backup ... get what you can't brake.
Tapatyped