depends on your lengths, same general budget ---candidates for fronts:
http://www.ebay.com/itm/GC-Fox-Shock...JYGR61&vxp=mtr
http://www.ebay.com/itm/97-Arctic-Ca...BYKn72&vxp=mtr
rear--progressive rate springs---not so much of an issue at the rear
http://www.ebay.com/itm/2004-Predato...NYKyOD&vxp=mtr
when buying used, number 1 thing to watch out for is shaft condition. don't buy any with visible rust, pitting, scoring or bends. they can be replaced, but cost about $55 per shaft new.