We want to sell our self-published book on the web in an e-Book format
for download or viewing on the web.  Adobe says I need a content
server to make the content secure from piracy, but they want $3,000. 
Is there another company in the US (preferably), offering this service
at a substantially reduced cost?

There's some useful information here:

http://www.adobe.com/products/contentserver/howtobuy.html

Thanks, but I don't think you read the question.  Adobe is who told me
I needed a content server and they want $3,000.