"Rent or buy?" is a question people ask about everything from housing to textbooks. It is also a question universities must consider when it comes to high-performance computing (HPC). With the advent of Amazon's Elastic Compute Cloud (EC2), Microsoft Windows HPC Server, Rackspace's OpenStack, and other cloud-based services, researchers now have the ability to quickly rent space and time on an HPC cluster, a collection of linked nodes that run as if they were one computer. Researchers who need to process vast amounts of data can buy an HPC cluster, rent a cloud-based solution, or opt for a hybrid approach.