Having your own server is always the cheapest option and will probably always will be. Although, you have to manage it, update it, secure the network etc. All

Having your own server is always the cheapest option and will probably always will be. Although, you have to manage it, update it, secure the network etc. All that takes time. If you are a company time costs money since you will probably have to employ people to do this. If you are an individual it means less time to work on whatever you're working on. But in essence, it is not cheaper it's more expensive. It have the possibility to be cheaper if you are the right company or person with the right problem. For example, buying disk space in the cloud is kind of expensive if you compare it with the hardware cost. I don't think a lot of file upload services use AWS or Azure to store files for this simple reason, it would not make any economical sense.