780 MT, dual monitor options

I have an Optiplex 780 MT and would like to run dual monitors. With only one onboard vga port and no dvi port. What is the most efficient way to do this without sacrificing quality. The only purpose of the dual monitors is for basic school work and not gaming. Would a splitter suffice, or would a video card be better? If so, which is the most economical video card with two ports that will fit and serve my basic needs? Any help would be appreciated. Thanks