http://www.npr.org/sections/money/2015/09/23/442921757/episo...
IRC, mattermost, email, Gitlab, Wekan, Skype/Google Hangouts/BigBlueButton.... there are plenty of tools to communicate without spending loads of cash.
If you have to pay for customers, then it's way too expensive.
I've seen a remote-based company put Slack to VERY good use, integrating it very tightly with their development process, I believe it definitely pays itself then.
If it's just a glorified IRC/XMPP, then definitely not.