Kicking around new ideas is fun for everyone, including the contact at the prospect you took so long to get hold off. After you stated your value proposition, you get the question "so how much does it cost?"
Obviously, at some point during a sales process, a budgetary figure and eventually a proposal needs to be provided. The timing to issue a proposal is crucial however.
A proposal should only be issued after the prospect wrote their own ROI document!
Other than that, you are just kicking around new ideas. And it's fun. But alas, no sale will be forthcoming. Even if a prospect states "we need this now, so just give us your price" you need to be sure the required steps in your sales process are covered before you hand out a proposal or pricing...no shortcuts.
Think of it like this. A prospect walks into a jewelry store and says "I want a watch. How much does it cost?" Where would you start? Probably "what type of watch? is it a gift? high-end, low-end? Everyday wear or for black-tie occasions?"
Business software offers many more challenges than choosing a watch. For one, there are many more users and stakeholders out there than the single owner of a watch.
Why is it then than some salespeople share a budget number or standard proposal for a prospect, just because they asked for one?
Good sales processes help prospects understand the value of the solution first, and the price only becomes an issue after the ROI has been determined.
There are exceptions - a prospect needs to replace a solution offered by one of your competitors; a project is running behind and needs a solution like yours to catch up; an integrator is recommending you as part of a larger implementation. However, even with these exceptions the ROI is usually clearly identified and the proposal is merely a data point.
Proposals are instruments to use towards the end of a sales cycle. They are not qualifiers for prospects unless you are targeting the market broadly and merely hoping to get lucky.