Additional monitor options

I currently am setting up to have a GTX 280 thanks to some price cuts that are hitting the market with the release of the GTX 295.  

I do not have the money to run SLI (nor the will to do so.  The GTX280 will be enough for now) but I am still thinking of upgrading to 3 moniters (because there is a hot deal on one).   How can I go about doing this without directly going SLI?  Can I just install a crappy video card to use as additional moniter support? or are their even remotely cheap alternate options that would just expand the number of DVI slots I have available?   I know I've done it before using on-board motherboard video adapter (being an additional moniter for a Voodoo 4, which used 3rd party special multi-display software if I recall) and later for a Geforce 4 (which I think used window's display manager >_> )  Since then I've never had an on-board video processor so I have never had more than 1 card in a computer non-SLI/crossfire. 

Any help/advise/input would be great.