ScreenSaver Start

How about a "try before you buy" version? I completely understand that to many 99 cents is not much but why spend money if this app does not work for me. For example, does it really work with Yosemite?

I'm not fond of reviewing or star-rating, so I'll just comment...

I've personally set my screensaver to start with an "Alt + \" combo, with Spark 3.0b9 which you can find here (curiously doesn't get listed in the suggestion box?!): http://www.macupdate.com/app/mac/14352/spark
Spark can tie even more "system" action to keyboard shortcuts (ie. shutting down with no warning, sleeping...), along with launching apps, documents, controlling iTunes and triggering menu items!

Despite being a really old and a sadly discontinued app, it still works almost flawlessly even in Yosemite (only the built-in script editor/triggering seems to be broken, but you can still launch AppleScript files for such purpose).
I can't operate a Mac without Spark... Highly recommended.
And free.

$1.99 for this... Wow... For free, without installing third-party software, you can simply assign a hot corner for the screensaver, from the system preferences. If you don't like it, or if you want screen-locking, simply open the 'Keychain Access' utility, from your 'Applications/Utilities' folder. From the preferences, set 'Show keychain status in menu bar'. That's it, you can now lock your screen from your menu bar.