Can anyone suggest the best way to drive costs down for our web conferencing needs? Right now we cannot afford to pay the ever increasing monthly fee as our usage of web conferencing increases.

I think you should use web conferencing appliances rather than hosted solutions to drive costs down. In hosted solutions you keep paying a monthly fee and also the costs go up for every additional user. In web conferencing appliances like RHUB - http://www.rhubcom.com/ - you pay only a one time fee and then you own the appliance. There is no recurring monthly fee and no limits on the number of users who can access your web conferencing sessions.