What is a virtual machine (VM)? In the simplest terms possible, a virtual machine (VM) is a virtual representation of a physical computer. As mentioned above, virtualization allows an organization to create multiple virtual machines—each with their own operating system (OS) and applications—on a single physical machine. A virtual machine can’t interact directly with a physical computer, however. Instead, it needs a lightweight software layer called a hypervisor to coordinate with the physical hardware upon which it runs.
For additional information visit IBM's 5 Benefits of Virtualization.
Oracle Virtual Box
I've been using Oracle Virtual box as my go to local VM. Last year, I picked up an HP quad-core workstation with 32 gb of RAM and I couldn't be happier. I'm also using Inland External 256 gb SSD's to make a self contained drive for work with a specific client.
Between 2015 and 2017 I used VMWare as my go to VM. VMWare is great software and commercially is very well respected.