I was speaking to a someone when I had questions about developing SharePoint integration for the product the company I work for, and got a quote for nearly $800. The company isn't using the SharePoint service, we are attempting to give our customers the ability to use it with our product. Is there no Development or trial accounts? or are we expected to pay for an account so that we can advertise for SharePoint (this makes no sense, but it seems to be what is being attempted)?
Install the 180-day trial for SharePoint Server 2013.
Or check Office 365 Enterprise E3 Trial.
If you want to use free version, you can use SharePoint Foundation 2013.