[brk]

There is no 'ballpark' price, it's mostly dependent on how valuable your product is to them. How much time or money does it save them? What are the alternatives (in terms of other software or non-action, etc.)

On top of that, what are YOUR costs to host and support the software? And, if you haven't considered that larger businesses often require significant hand-holding in terms of support and training, you need to factor that in also.

The only thing I can really say is that getting large businesses to pay can be a PITA, especially at first. You might want to understand how/when they pay new vendors (I've dealt with some large Corp that process new vendors once per quarter. Come in on the 2nd week of the quarter and its going to be a while before you get paid at first).