Ask HN: Cloud Hosting for Intermittent Tasks?

I have a personal project (a raytracer) for which testing means the occasional high-compute job that takes a long time on my workstation and makes it very hot (and unusable for anything else). I'm wondering if there's a cloud hosting provider that offers pricing for intermittent high-workloads. Ideally it would be priced based on compute time, but otherwise it could be by the minute or hour. I don't want to pay a full monthly fee for resources that are only used a handful of times in a day a few days a week, and this being a personal project it isn't large enough to scale up and down at the level of a cluster.