Calling locations will be really convenient for you and will save you time travelling/fuel.

Call Autobarn, SupercheapAUTO, Repco, JDMyard. If you have patients try the US eBay, however be careful imitations.

Make sure tell each vendor "Hey these guys sell these at this price, could you do better?" And continue on with other vendors and see which one will win best price. It will give you a better idea on how much the actual "Cost Price" is.

JDMyard quoted OEM brand new for $100~$150 B-series. OEM is best will last for ages + made for the engine, in the long run it is also an investment.