However, it should also be pointed out that it's also a deploy-your-own-unpaid-system-administrator-job. A lot of the value in SaaS products is the service provided of someone else maintaining it. The maintenance and security patching for running all this stuff, especially on the open Internet, that would quickly become a part time job.
So, I'd say that for most people with a limited time budget, it's worth the cost to simply find a high quality, paid SaaS provider for many of these services.
An example on from list: deploying your own email server and depending on it for your important communications is something that almost nobody should attempt on their own. Instead, most people should look to migrate from free providers that could do things like close your account/delete your data at any time, to paid ones that treat you like a paying customer.