Hi Stevo,
Bit late with this reply, so not sure if you've found a suitable CRM solution yet.
This is a big (and important) question and, without knowing all your CRM requirements, is not really possible to answer.
While many CRM's offer free trial versions, these might be time restricted for typically 30 days.
There are a few that offer full free versions, sometimes supported by advertising. An example here would be Etelos CRM for Google Apps. Nice flexible product that dovetails neatly with Google. FreeCRM have a free version too, as does EssentialPIM.
You can find other potential web based CRM's here: Small Business CRM Solutions
Please feel free to throw more questions my way, if need be.
Good luck,
Perry