[srehnborg]

Having sold two different SaaS products over the last few years, I would do a couple of things.

Make it clear on the website. $20.00/user per month. To most people, that is clear that they will be charged each month that price.

In addition to that, in your terms & conditions, you can explain the exact details of the terms.

Depending on the price of the product, I wouldn't waste too much space on the website explaining that they will be auto-renewed as it should be self explanatory and it could cause confusion.

Also, do you have a sales team or do you rely on people to just sign up on the website?