Franconian

Hi folks, I just had my Townace serviced and the garage quoted me ridiculously priced spares. I need new front brake discs / pads, spark plugs, air filter, fuel filter. Quote was $700!!! Where do you guys buy your spares from? I'm located in Sydney, checked out Ebay, but not really found what I was looking for. It's an old van and I am happy with cheap aftermarket parts just to get it going for a bit longer. Cheers, Frank