Forum OpenACS Q&A: Re: Annual cost per user for OpenACS
Viaro.Net is one provider that supports OpenACS.
There are many other companies like SolutionGrove.com, ACSPropel.com that also provide OpenACS consulting and hosting.
My company, Zill.Net, provides OpenACS hosting (but not programming), however in our case we charge based on resources used - there is basically a choice between being on a shared server or having a dedicated server.
A shared server could host up to say, 400-2000 users depending on how heavily each uses the system and cost $50 a month ($600 per year).
At the other end of the spectrum, I have a customer with a 16GB RAM customized server dedicated to only their use that could probably host 50,000 or more users at a cost of about $15,000 per year. In such a case, each user would be about 30 US cents per user.
This situation for hosting has worked pretty well for me. Although it has not been an easy sell of the system because what people see when they check the web for .lrn is higher education sites. I have only found I elementary school that said they were using it, but they didn't have much at all.