Digital Ocean and Linode are good services. Scaleway started with ARM servers but now offers x86-based servers at a very low price point. Unlimited bandwidth too. I've also used vultr.com. As @eulid55 says, lowendbox.com is a good resource, but some would consider offerings there a bit TOO low-end. Your mileage may vary.
Others that come to mind are OVH and online.net. If you really just need shell access, sdf.org is a possibility.
