you can find trias on Ebay, or any fine art shop. Thing is, you'd only get the new version which is honestly not very good: the old version had three pens, all divided on a pantone chart, and you could buy refill tanks; Now you've got always the three pens, but the thinner is much less precise, you don't have the pantone chart anymore (I was told it was too expensive for trias to re-buy the rights for production)and if you want to refill the pens, well you can't, you have to buy another cotton-thingie (how do you call the ink-cotton stuff they put in markers?) and it's almost the same price as buying a new tria.

So thankfully, I managed to buy as many refill and trias as I could a while back...I should be safe for anoher few years.