ALWAYS check ebay you can find some great stuff on there for a great price. I just go 96 woody's gold digger carbide tipped studs for $40 instead of over $100 from the parts stores
List price on each half is $41.47. I think it would be better to buy new ones; it might be difficult to find used that aren't cracked already! P/N's are 514 053 167 upper, 514 053 360 lower. Have fun!