These are ongoing services so a once off payment doesn't make sense for the business. The alternatives are self-hosting and free services, self hosting is great. If you are using free services though, they could disappear too, and you have to question the business model of anyone givingyou something for nothing.

At least if you are paying for it you are entering into a contract of service from the provider which gives you a lot of legal recourse and leverage and also supports the business so that they do keep providing you the service.