Anyone got any prices on used 300ex's??

Try ebay.com
and
Try cycletrader.com
and
Try looking under the classifieds section on excite.com
If you are wondering what they usually cost it really depends on what you want. A 97-01 will cost about $3000-3500 and something a little older costs between $1500-3000
I paid $2100 for a 93 this past december.