I've had some real nightmares with my '96 Legacy, but one thing is for sure, I've found some bargains (keep in mind these are Canadian prices):
New catalytic installed $800-1000 Found one used $500
Snow tires on RIMS new $1000 Bought one set for $130, wrong size, sold for $300! Found correct size in classfied ads $450!!
Oxygen sensor new, installed $350 Over the internet, self installed $70