Am I correct that the unlimited version is $19.99 and installation is $10.00?
Yes, that's correct.
That price will include cron setup on my site and will generate google, yahoo, msn and what other sitemaps?
You should provide hosting control panel access (additionally to FTP login) in case if you want to have cron task setup.
How long does it take for you to setup?
Installation is usually done within 24 hours.
If my site has 40,000 links to map how long will it take to generate that sitemap?
it depends on the page generation time mainly, since it crawls the site similar to search engine bots.
For instance, if it it takes 1 second to retrieve every page, then 1000 pages will be crawled in about 16 minutes.
Some of the real-world examples of big db-driven websites:
about 35,000 URLs indexed - 1h 40min total generation time
about 200,000 URLs indexed - 38hours total generation time