BleepingComputer.com: Cheap options for three monitors

Ok, I'm currently utilizing a panasonic toughbook utilizing Windows XP on one network and a newer Dell Inspiron desktop version on a seperate network with both systems running through a KVM to a single monitor utilizing a microsoft wireless keyboard and mouse setup. I want to expand from a single monitor to a three or four monitor setup and was wondering what the best most cost effective method would be. I only have one vga output on the toughbook and adding an additional card there is not an option as it is a work computer, however, I do have vga, digital, and hdmi outputs on the Dell desktop. Any ideas would be greatly appreciated.