Disk Drill for Mac is listed as a free method because it provides a complete preview of the files that it can recover before costing you a cent.
The most effective way of restoring data on a Mac without software is with a backup. Backing up your computer should be a part of your regular routine if you value your data.
Probably not. You will quickly learn if you can recover with a backup or the Trash. If not, you should move on to a quality data recovery tool like Disk Drill to get your files back.