Sorry, but even for a team of 6 people if you can't muster $300/yr (breaking down to $25/mo or $4/user-mo) you aren't bootstrapping. You're being inefficient, and perhaps even reckless with your endeavor. (Unless you're building a competitor).
Sometimes it's about the pennies. But other times, especially early, it won't be these types chunks of money that kill you. I used to go on CL and do user-studies for $50 a pop and resell the gift cards for cash or amazon credit. So it's hard for me to believe that what you are building can't spare an hour of work to fund baseline communication systems that are pretty well supported.
Better pay those $300 and have your people and you 100% focus on your product, creating it, marketing it and selling it. Than dealing with spam rules or downtime servers.
That is why heroku exists right? Otherwise only linode or ec2 could make business. Now if you have free time (you shouldn't) then, it is a whole different story. I agree with you.
Sometimes it's about the pennies. But other times, especially early, it won't be these types chunks of money that kill you. I used to go on CL and do user-studies for $50 a pop and resell the gift cards for cash or amazon credit. So it's hard for me to believe that what you are building can't spare an hour of work to fund baseline communication systems that are pretty well supported.