I am going through this right now. What I did was price it monthly, ask for annual payment up front, and charge more. I am charging $100/month for a drop-in en

I am going through this right now. What I did was price it monthly, ask for annual payment up front, and charge more. I am charging $100/month for a drop-in enterprise tool for SME businesses. Don't forget to charge for services too. So the initial invoice is $1-2k and then $100/month. It is somewhat annoying to setup the whole app inside their intranet, so you may need to research code mangling tools (protect your IP somewhat) and installing deps on their server, but otherwise just charge a lot more and provide service.