Web-based CRM Software

Hi,

We are looking for a low cost ($500 or less) CRM solution (Customer Relationship Management).

I would prefer something that is web-based, or at least available over the Internet.

So far, the options I’ve seen are:

-CA’s eCRM suite (too expensive)
-MS Exchange server
-Lotus Domino/Notes
-A few contact management packages, like Symantec ACT!, Goldmine, and ContactPlus Pro

We are running NT server, and there would be at least 4 people using the CRM system (possibly more in the future)

Any suggestions or ideas would be greatly appreciated.

Thanks in advance.

-Daniel