[dba-Tech] Sharepoint - What does it cost?

I have a potential customer who might benefit from using Sharepoint.  They
are only about 100 people, but have sales and field reps in several places
in the world.  What does Sharepoint cost?  

I've read before that a list in Sharepoint can be connected to an Access
database.  If my customer does use Sharepoint, then I believe I can give him
some database functionality collaborating with widely dispersed people.  Has
anyone used Sharepoint with Access?

Thanks!

Dan