Maybe Word and Excel aren't the best examples, but I don't doubt they could have succeeded if they only gave it away to EDUs and had a base plan for consumers and a self-service enterprise plan. Microsoft had a foothold in desktop market so pushing Office and getting users to use it was easy. And once you try it, it does sell itself.

But I think Trello, Craigslist and Wikipedia are great product examples. You need not have a sales team to scale everything.

You can achieve that with a great product, great customer support, digital marketing and word of mouth.