download Yosemite

Apple has removed both Mavericks and Yosemite from the App Store.

Unless you've downloaded it before it was removed there is no way to get a copy.

Nope.

It's gone. And soon so will be El Capitan.

The only other way is to buy a Mac or hard drive with it already installed, and if someone saved a slipstreamed version of it willing to give up its license.

You can try asking at an Apple Store.