Sorry for coming late to the party. I was busy.
Provisional applications are measured by the exact same legal standard for sufficiency as real, non-provisional applications. If you hope for a big discount for your application merely because it's "provisional", you're looking for a provisional application that is not legally sufficient. And, that would likely provide no protection whatsoever. There is no partial credit in patents; they're either sufficient or they're not.
That's not worth 10k.
That might be right, since I can typically write complete, moderately complex patent applications for less. However, some inventions are ridiculously complex -- some costing six figures for the application (I've heard tale of 6-figure responses to office actions; still trying to grok that). So, $10k could be a huge discount, albeit unlikely.