Comment by intrasight

I ran a SaaS for 10 years. Two products. Profitable from day 1 as customers paid $500/month and it ran on a couple of EC2 instances as well as a small RDS database.

Another thing one has to consider is the market size and timeframe window of your SaaS. No sense in building for scalability if the business opportunity is only 100 customers and only for a few years.