I spent approx 260 on the ebay timing kit, includes timing belt, all idlers, tensioner, water pump & seals. All quality brand name Japanese made parts. I don't use the black seals however, I prefer oem for cam and crank seals. some people change cam and crank seals whenever they are there, I only do as required.
I think I forgot to put on the original list valve cover gasket kits including spark plug gaskets and bolt gaskets. Fel pro makes a good kit, and I have had good luck with erastic (not sure on the spelling). Available on ebay for approx 15-25.00.
The dealer parts came out to about 165.00. You will spend another 40-50 on oil, coolant, sealant, etc. There are a few dealers who have pretty good prices for usmb referrals.
You may want to consider having the heads surfaced and leak checked at a machine shop, depending on condition. Try to find a shop that knows subaru, easy to do here in the Northwest, not sure about SoCal.