I'm not on here to defend the price. That would be pointless as I'd lose every argument as it hasn't sold. I know it's an international forum, I was just hoping only Australians would respond. Don't take this the wrong way but as firegrey has alluded to, international opinions count for shit.
Firegrey if you were selling what would be your lowest mark. Taking into consideration ebay's 10% cut? And you were not desperate to sell.
It's always different depending on what the seller wants from it, but from a buyer perspective I would pay over $300 for an Australia 3DS XL with 4 mario games.
The fact that it's a US model means different things to different buyers, there is ofcourse the fact that you get eShop games a lot cheaper using the US model, but you don't have the convenience of buying from stores, which is a lot more popular than buying digitally, especially considering how slow Australian internet is..
A lot of buyers will expect that a US 3DS must be a lot cheaper than and Australian 3DS, though when I have looked into this I have found that the opposite is actually true, I bought my Australian 3DS XL brand new for only $200 off ebay, with some silly naruto game (the seller didn't even detail that he would send any game with it) when to order off Amazon (the only place without great difficulty to import things to Australia) it would cost $200 AUD + Shipping with the current $15 USD off.
In comparison with other deals, you have a very low asking price but without knowledge of demand on the US model her in Australia, it may not be sold instantly like a good deal should.
I personally believe that you could sell it $25 higher if you were to keep it up there for over two weeks, it just really depends on how patient you want to be.
If you are content with the price there at the moment, I would leave it up there for 2 weeks and if in the unlikely case, it hasn't sold, then pick the best offer, though it would be easiest to just accept an offer of $265+ as soon as it comes up because $10 shouldn't really be a big deal.