Way to set up e-mail to automatically file a sender's e-mail into a folder?

Y has mail plus but it costs money.

Top right of your mailbox you should have a section which says "mail alerts" ( you can also click on "options" (top right of your screen when you click on Invox) then chose "filters" and create the conditions that will select emails to go in a specific folder when they come in. You can even chose a function that will alert your mobile device when you receive a particular email (say your boss for example!).