It depends on which set the card is from. If it is the original, black bordered card from Antiquities, about $10 as of May 2010. Otherwise, under a dollar, though the fifth edition printing seems to...
It all depends on what they are. Easiest way to find out is to check websites and see what they sell for. Best place to check www.findmagiccards.com and search your card and look at average prices....
The six-card packs are about a dollar, the 15-card packs are about three dollars, the intro packs are about twelve dollars, and any pack bigger than that ranges from twenty to thirty dollars.