In enterprise, the cost of free is perception.

Perceived value is – at least up front – everything. It is the push required to get a prospective customer to sign up and trial– to take the time to find value in your product.

Free is great– it dramatically lowers the barrier (cost, approval, time to activation, etc.,) between a prospect and your products value. In many cases, this is where the market is headed. It's the world of SaaS, BUT it is important to understand that there is a HUGE difference between a free trial and a free (or cheap) product.

In our early days (still living them), it happened time and time again– until I saw the pattern. You land a meeting with a C-Level exec at a F500-2000. They’d love the product, the timing would be right, they were ready to get started:

"So how much does it cost."
"Well, your first month is free, but I'd like to include you in our 3-month pilot program."
"Oh."

And that's that. The interest would disappear in an instant. Why? Because surely an enterprise grade, solve-all-of-our-problems product is worth more than free, even for a trial. As soon as I started asking for money - real money - my results improved.

"So how much does it cost."
"Well, normally it's $XX,000 per month, but I'm willing to work with you at $X,000 over the course of a
3 month pilot program while we ensure you are successfully on-boarded." 
"That sounds reasonable, I'll talk with our CXO about next steps."

Now we're talking.

Free is great, but make sure you're using it properly. 

Enterprise customers don't want free, they want a clear return on investment, support, and uptime. Charge them for it, they want you to.