Well the good new is that itís your companyís money and not yours. The bad new is your really donít have a choice that I know of. Syncing public folders is a very complicated and is internal to Exchange so if there is a cheep alternative out there buyer be ware. $550 is a small amount of money to pay as apposed to hosing up your BES or Exchange server with some cheep software alternative. But if you do find something let us know.
I use Outlook PCS. I believe it is a free download from Microsoft. It allows me to sync public folders to my contact list. So I have setup my departments public folder contact list to sync with my contact list using PCS. It adds a category to all those contacts as well so with 4.0 you can filter by that category if you want. I just have to manually sync with the public folder from within outlook periodically and any changes get sent to my Blackberry wirelessly. Works pretty well for a good work around.
I have used Outlook Pocket Contact Sychronizer for awhile also. It updates your contact list by incorporating the information on a public folder contact list into your personal contacts. If you have a lot of contacts in your selected public folder, your contacts folder will include all of them. As far I have found, it does not sync calendar items.