You can open a free app service on Windows Azure. This would give you 1 GB of storage for your web files, which can be any files including those generated from a click-once deployment, including the updated files that you use for the auto-update
feature. However, be aware that the free version only provides for free a download volume of 165 MB per day.
https://azure.microsoft.com/en-us/pricing/details/app-service/