This is both a time and a sanity saver: Lastpass. It is a program that can live on your desktop, your browsers AND your mobile phone that will securely store all of your logins, credit cards and even standard information you repeated use to fill in forms online (name, address, email, phone, etc). with one click (ok, maybe 2 clicks) you can automatically fill in any login information or form on any website.
The best thing is that it syncs across all platforms and has a website you can log into to retrieve data. Therefore, no matter where you are or what machine you are using, you never have to worry about forgetting a password or the credit card you wanted to use to make a purchase.