I tried LastPass, but didn't trust them, so I found https://www.passwordstore.org/ some year ago. I can't emphasize enough how good it is, mainly because it is so dead simple and transparent in how it works, and also because it has great bash integration, and uses git which makes it easy to sync between your machines. There is also a firefox plugin that integrates with it, but I don't really see that you need it: it is so easy to use at a prompt.