RailsPlayground offers VPSs starting at $20 per month with optional management service that costs $15 per month [1]. They offer VPS images that include control panels: cPanel ($12 per month) or Virtualmin (free).
That said, you will need to familiarize yourself with the OS, control panel, and the other software that's included in the VPS image that you use. With this in mind, I think your time would be better spent learning how to set up a server. One of the biggest regrets of my career is the time I wasted trying to take shortcuts (e.g., using text editors other than Vim and Emacs).