I don't know they charge such a premium for one ounce coins.What you can do is buy your smaller perth mint coins on ebay from one of the bullion dealers for about two or three dollars less than the mint.Check it out I found there prices for 1kg bars and 100oz bars to be very close to the spot price.
Also if you go to perthmint online site they show you there volume breaks which they don't tell you over the phone.
The mint tried to rip me of once I asked for 100 half oz coins they said no we only have 99 coins in stock at this time would I like to take 99.I said no I'am happy to wait for that extra coin.I checked my invoice and the coins were 1 dollar less than there list price? Two days later I registered for their online trading and they list all their volume breaks.
